[ccp4bb] Twinned data and maps
Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
Re: [ccp4bb] ANISOU
Dear Tim Fenn, That's better : ) On Mon, 16 Mar 2009 11:01:34 +0800 Sheng Li biol...@gmail.com wrote: Please read the coordinate file with alwyn's O, and then save it to another file. The ANISOU lines will be removed. only if you use s_a_i - pdb_read will preserve ANISOU. It might be easier to just grep them out: grep -v ^ANISOU foo.pdb bar.pdb -Tim . = = = = = = = = = = = = = = = = = = = =
Re: [ccp4bb] ANISOU
Dear friends, if the data is of high enough resolution, wouldn't be more reasonable to attempt anisotropic refinement (constrained with TLS or refining individual anisotropic ADP), or mixed one - some atoms are isotropic and some anisotropic, rather than struggle with file conversions and getting rid of ANISOU in order to remove escape the reality? -:) There is a bunch of programs out there that can do it for you! Cheers, Pavel. On 3/15/09 10:55 PM, Tim Fenn wrote: On Mon, 16 Mar 2009 11:01:34 +0800 Sheng Li biol...@gmail.com wrote: Please read the coordinate file with alwyn's O, and then save it to another file. The ANISOU lines will be removed. only if you use s_a_i - pdb_read will preserve ANISOU. It might be easier to just grep them out: grep -v ^ANISOU foo.pdb bar.pdb -Tim
Re: [ccp4bb] images
The deposition of images would be possible providing some consistent imagecif format was agreed. This would of course be of great use to developers for certain pathological cases, but not I suspect much value to the user community - I down load structure factors all the time for test purposes but I probably would not bother to go through the data processing, and unless there were extensive notes associated with each set of images I suspect it would be hard to reproduce sensible results. The research council policy in the UK is that original data is meant to be archived for publicly funded projects. Maybe someone should test the reality of this by asking the PI for the data sets? Eleanor Garib Murshudov wrote: Dear Gerard and all MX crystallographers As I see there are two problems. 1) Minor problem: Sanity, semantic and other checks for currently available data. It should not be difficult to do. Things like I/sigma, some statistical analysis expected vs observed statistical behaviour should sort out many of these problems (Eleanor mentioned some and they can be used). I do not think that depositors should be blamed for mistakes. They are doing their best to produce and deposit. There should be a proper mechanism to reduce the number of mistakes. You should agree that situation is now much better than few years. 2) A fundamental problem: What are observed data? I agree with you (Gerard) that images are only true observations. All others (intensities, amplitudes etc) have undergone some processing using some assumptions and they cannot be considered as true observations. The dataprocessing is irreversible process. I hope your effort will be supported by community. I personally get excited with the idea that images may be available. There are exciting possibilities. For example modular crystals, OD, twin in general, space group uncertaintly cannot be truly modeled without images (it does not mean refinement against images). Radiation damage is another example where after processing and merging information is lost and cannot be recovered fully. You can extend the list where images would be very helpful. I do not know any reason (apart from technical one - size of files) why images should not be deposited and archived. I think this problem is very important. regards Garib On 12 Mar 2009, at 14:03, Gerard Bricogne wrote: Dear Eleanor, That is a useful suggestion, but in the case of 3ftt it would not have helped: the amplitudes would have looked as healthy as can be (they were calculated!), and it was the associated Sigmas that had absurd values, being in fact phases in degrees. A sanity check on some (recalculated) I/sig(I) statistics could have detected that something was fishy. Looking forward to the archiving of the REAL data ... i.e. the images. Using any other form of data is like having to eat out of someone else's dirty plate! With best wishes, Gerard. -- On Thu, Mar 12, 2009 at 09:22:26AM +, Eleanor Dodson wrote: It would be possible for the deposition sites to run a few simple tests to at least find cases where intensities are labelled as amplitudes or vice versa - the truncate plots of moments and cumulative intensities at least would show something was wrong. Eleanor -- === * * * Gerard Bricogne g...@globalphasing.com * * * * Global Phasing Ltd. * * Sheraton House, Castle Park Tel: +44-(0)1223-353033 * * Cambridge CB3 0AX, UK Fax: +44-(0)1223-366889 * * * ===
Re: [ccp4bb] Twinned data and maps
I am not sure if there is any way of avoiding model bias if the coordinates are included regardless of whether there is twinning or not - my preferred method is to set the occupancies of suspect regions to 0.00 then do refinement of the better parts of the model and then check maps again and rebuild as the maps indicate.. Eleanor Walter Kim wrote: Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
Re: [ccp4bb] images
Hi I'm afraid the adoption of imgCIF (or CBF, its useful binary equivalent) doesn't help a lot - I know of three different manufacturers of detectors who, between them, write out four different image formats, all of which apparently conform to the agreed IUCr imgCIF standard. Each manufacturer has its own good and valid reasons for doing this. It's actually less work for me as a developer of integration software to write new code to incorporate a new format than to make sure I can read all the different imgCIFs properly. On 16 Mar 2009, at 09:32, Eleanor Dodson wrote: The deposition of images would be possible providing some consistent imagecif format was agreed. This would of course be of great use to developers for certain pathological cases, but not I suspect much value to the user community - I down load structure factors all the time for test purposes but I probably would not bother to go through the data processing, and unless there were extensive notes associated with each set of images I suspect it would be hard to reproduce sensible results. The research council policy in the UK is that original data is meant to be archived for publicly funded projects. Maybe someone should test the reality of this by asking the PI for the data sets? Eleanor Garib Murshudov wrote: Dear Gerard and all MX crystallographers As I see there are two problems. 1) Minor problem: Sanity, semantic and other checks for currently available data. It should not be difficult to do. Things like I/ sigma, some statistical analysis expected vs observed statistical behaviour should sort out many of these problems (Eleanor mentioned some and they can be used). I do not think that depositors should be blamed for mistakes. They are doing their best to produce and deposit. There should be a proper mechanism to reduce the number of mistakes. You should agree that situation is now much better than few years. 2) A fundamental problem: What are observed data? I agree with you (Gerard) that images are only true observations. All others (intensities, amplitudes etc) have undergone some processing using some assumptions and they cannot be considered as true observations. The dataprocessing is irreversible process. I hope your effort will be supported by community. I personally get excited with the idea that images may be available. There are exciting possibilities. For example modular crystals, OD, twin in general, space group uncertaintly cannot be truly modeled without images (it does not mean refinement against images). Radiation damage is another example where after processing and merging information is lost and cannot be recovered fully. You can extend the list where images would be very helpful. I do not know any reason (apart from technical one - size of files) why images should not be deposited and archived. I think this problem is very important. regards Garib On 12 Mar 2009, at 14:03, Gerard Bricogne wrote: Dear Eleanor, That is a useful suggestion, but in the case of 3ftt it would not have helped: the amplitudes would have looked as healthy as can be (they were calculated!), and it was the associated Sigmas that had absurd values, being in fact phases in degrees. A sanity check on some (recalculated) I/ sig(I) statistics could have detected that something was fishy. Looking forward to the archiving of the REAL data ... i.e. the images. Using any other form of data is like having to eat out of someone else's dirty plate! With best wishes, Gerard. -- On Thu, Mar 12, 2009 at 09:22:26AM +, Eleanor Dodson wrote: It would be possible for the deposition sites to run a few simple tests to at least find cases where intensities are labelled as amplitudes or vice versa - the truncate plots of moments and cumulative intensities at least would show something was wrong. Eleanor -- === * * * Gerard Bricogne g...@globalphasing.com * * * * Global Phasing Ltd. * * Sheraton House, Castle Park Tel: +44-(0)1223-353033 * * Cambridge CB3 0AX, UK Fax: +44-(0)1223-366889 * * * === Harry -- Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC Centre, Hills Road, Cambridge, CB2 0QH
[ccp4bb] AW: [ccp4bb] Twinned data and maps
Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
Re: [ccp4bb] AW: [ccp4bb] Twinned data and maps
Hi - I thought that both phenix and refmac output map coefficients corresponding to de-twinned data - or do I get this wrong? I am also wondering what is the context of poor and if it has to do with twinning, or simply if the starting model is not so good. In what was are these poor maps different than the refmac5 model biased maps? From what I have seen also from your previous email its hard to advice. Its not clear if the Phaser solution is correct, how good the search model was, how the refinement goes. I would suggest to post these details so maybe we could send more detailed comments. Tassos On Mar 16, 2009, at 11:24, Clemens Steegborn wrote: Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter P please don't print this e-mail unless you really need to Anastassis (Tassos) Perrakis, Principal Investigator / Staff Member Department of Biochemistry (B8) Netherlands Cancer Institute, Dept. B8, 1066 CX Amsterdam, The Netherlands Tel: +31 20 512 1951 Fax: +31 20 512 1954 Mobile / SMS: +31 6 28 597791
[ccp4bb] EMBO / MAX INF2 Practical Course on Structure Determination in Macromolecular Crystallography held at the ESRF, June 15-19, 2009.
* EMBO / MAX INF2 2009 a Practical Course on* *Structure Determination in Macromolecular Structure* **ESRF-EMBL, Grenoble, France, 15 - 19 June 2009 An EMBO / MAX INF2 2009 course on Structure Determination in Macromolecular Structure will be hosted by the ESRF in Grenoble, France from 15 to 19, June 2009. This practical course addresses young scientists who intend to apply single- and multiple-wavelength anomalous scattering (SAD MAD) methods in macromolecular structure determination. The course aims to impart the theoretical and practical basis for the 3-dimensional structure determination of bio-macromolecules using these techniques. Through a series of lectures, software demonstrations, practicals and tutorials, participants will get insights into all aspects of the structure determination process including beamline instrumentation, data collection and processing, heavy atom substructure determination, phasing and model building. There will also be sessions focusing on automated structure solution procedures and newer methods which exploit small anomalous scattering signals from crystals of native macomolecules. The number of participants is limited to 20 and the deadline for application is May 1^st , 2009. More detailed information, the course programme and instructions as to how to apply to attend the course can be found in the webpages at the URL: http://cwp.embo.org/pc09-05/. -- Matthew Bowler Macromolecular Crystallography Group European Synchrotron Radiation Facility B.P. 220, 6 rue Jules Horowitz F-38043 GRENOBLE CEDEX FRANCE = Tel: +33 (0) 4.76.88.29.28 Fax: +33 (0) 4.76.88.29.04 http://www.esrf.fr/UsersAndScience/Experiments/MX/About_our_beamlines/ID14-2/ =
Re: [ccp4bb] images
Dear Colleagues, The issue Harry is describing, of people writing multiple variations of image formats even though all of them are imgCIF is not really a problems with the images themselves. Rather it is a lack of agreement on the metadata to go with the images. This is similar to the problem of lack of consistency in REMARKS for early PDB data sets, which eventually required the adoption of standardized REMARKS and reprocessing of almost all data sets. I don't think it would have been easier to reprocess those data sets if the original data sets had also had their coordinates and sequences recorded with wide variations in formats. The advantage of using imgCIF for an archive is not that it would force everybody to to their experiments using precisely the same format, but that, because it is capable of faithfully representing all the wide variations in current formats, it would allow what we now have to be captured and preserved and, when someone needed a dataset back, to be recast in an format appropriate to the use. Think of it as that little figure-8 plug and socket we are able to use to adapt our power cords for travel around the world. There are other possible hub format (NeXus, DICOM, etc.), but the sensisble thing for an archive is to choose one of them for internal use, just as the PDB uses a variation on mmCIF for its internal use to allow it to easily deliver valid PDB, CIF and XML versions of sets of coordinates. For an archive, the advantages of using imgCIF internally, no matter which of the more than 200 current formats were to be used at beam lines and in labs, is that it would not be necessary to discard any of the metadata people provided and it could be made to interoperate easily with the systems used internally by the PDB for coordinate data sets. For many of the formats in current use, there is no place to store some of the information people provide and translation to other formats can sometimes be much more difficult than one might expect unless additional metadata is provided. Even such obvious things as image orientations are sometimes carried separately from the images themselves and can easily get lost. Don't let the perfect be the enemy of the good. Archiving images in a common format, such as imgCIF, or, if you prefer, say, in the NeXus transliteration of imgCIF, would help to make some very useful information accessible for future use. It may not be a perfect solution, but it is a good one. This is a good time to start a major crystallogrpahic image archiving effort. Money may well be available now that will not be avialable six month from now, and we have good, if not perfect, solutions available for many, if not all, of the technical issues involved. Is it really wise to let this opportunity pass us by? Regards, Herbert = Herbert J. Bernstein, Professor of Computer Science Dowling College, Kramer Science Center, KSC 121 Idle Hour Blvd, Oakdale, NY, 11769 +1-631-244-3035 y...@dowling.edu = On Mon, 16 Mar 2009, Harry Powell wrote: Hi I'm afraid the adoption of imgCIF (or CBF, its useful binary equivalent) doesn't help a lot - I know of three different manufacturers of detectors who, between them, write out four different image formats, all of which apparently conform to the agreed IUCr imgCIF standard. Each manufacturer has its own good and valid reasons for doing this. It's actually less work for me as a developer of integration software to write new code to incorporate a new format than to make sure I can read all the different imgCIFs properly. On 16 Mar 2009, at 09:32, Eleanor Dodson wrote: The deposition of images would be possible providing some consistent imagecif format was agreed. This would of course be of great use to developers for certain pathological cases, but not I suspect much value to the user community - I down load structure factors all the time for test purposes but I probably would not bother to go through the data processing, and unless there were extensive notes associated with each set of images I suspect it would be hard to reproduce sensible results. The research council policy in the UK is that original data is meant to be archived for publicly funded projects. Maybe someone should test the reality of this by asking the PI for the data sets? Eleanor Garib Murshudov wrote: Dear Gerard and all MX crystallographers As I see there are two problems. 1) Minor problem: Sanity, semantic and other checks for currently available data. It should not be difficult to do. Things like I/sigma, some statistical analysis expected vs observed statistical behaviour should sort out many of these problems (Eleanor mentioned some and they can be used). I do not think that depositors should be blamed for
Re: [ccp4bb] AW: [ccp4bb] Twinned data and maps
But dont all twinned refinement programs output detwinned terms for a map? Certainly REFMAC and SHELX do. Eleanor Clemens Steegborn wrote: Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
Re: [ccp4bb] AW: [ccp4bb] Twinned data and maps
As far as I know map coeffiicient correspond to detwinned data. But using detwinned data may not be a good idea. It would be good to see what are R factor. Another thing to consider is that different program may use different flags for free R and it may cause some problem. What are Rfactors, completeness, percentage of freeR reflections? These are printed by all programs. If your solution is wrong and you are using twin refinement even if you do not have twinned crystals your R factor can be as low as 50% (that is theoretical limit for random Rfactor when one data are from twinned and another from untwinned crystals). If you have perfect twin and you are modelling twin (using twin refinement) then your random Rfactors can be even smaller. regards Garib On 16 Mar 2009, at 11:51, Eleanor Dodson wrote: But dont all twinned refinement programs output detwinned terms for a map? Certainly REFMAC and SHELX do. Eleanor Clemens Steegborn wrote: Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
[ccp4bb] AW: [ccp4bb] AW: [ccp4bb] Twinned data and maps
Yes, Phenix default output (for twinned data) is detwinned, like the one from Shelxl; didn't know for the new Refmac twin option - but I understand from this posting and Garib's that it also detwins if the twin option is used ... So considering that the Shelxl-derived density looked bad, I definitely agree with Tassos (and apparently didn't make that point clear enough) that other reasons for bad density than twinning have to be considered ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Eleanor Dodson Gesendet: Monday, March 16, 2009 12:52 PM An: CCP4BB@JISCMAIL.AC.UK Betreff: Re: [ccp4bb] AW: [ccp4bb] Twinned data and maps But dont all twinned refinement programs output detwinned terms for a map? Certainly REFMAC and SHELX do. Eleanor Clemens Steegborn wrote: Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter
Re: [ccp4bb] AW: [ccp4bb] Twinned data and maps
But wouldn't detwinning be problematic with nearly perfectly twinned data? I'll post my own question about separately to not hijack the thread... On Mon, 2009-03-16 at 11:24 +0100, Clemens Steegborn wrote: Hi Walter, You should definitely detwin data for map calculation if you have a significant twinning fraction (and only for maps; keep using the twinned data set for refinement). We use the CCP4 program detwin. BUT if Shelxl gives bad density, maybe that's simply what you have, a bad density map - because output from Shelx is already detwinned! BTW, we observed that different programs handled different cases differently well; I would suggest ALWAYS to try more than one program, and also to try Phenix ... Best Clemens -Ursprüngliche Nachricht- Von: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] Im Auftrag von Walter Kim Gesendet: Monday, March 16, 2009 7:22 AM An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Twinned data and maps Hi again, Thanks for your insight into refinement tools for twinned data. I have a couple of twinned data sets that are nearly perfectly pseudomerohedrally twinned. I've begun to refine my data in Refmac5 (using the automated twin refinement), CNS (using the twin inputs) and Shelxl; I'm testing out the different refinement programs to evaluate the best strategy for the refinement. However, I would like to start making maps. 1. Refmac5 - outputs an mtz that is model-biased 2. CNS - maps made via model_map_twin.inp are poor 3. Shelxl - the maps generated in coot from the.fcf file are poor Are there better ways to make cleaner maps with my twinnned data that are less model-biased that I can try to build into? Should I detwin the data and make maps from that (but continue to refine against the twinned data)? Thanks, Walter -- Edwin Pozharski, PhD, Assistant Professor University of Maryland, Baltimore -- When the Way is forgotten duty and justice appear; Then knowledge and wisdom are born along with hypocrisy. When harmonious relationships dissolve then respect and devotion arise; When a nation falls to chaos then loyalty and patriotism are born. -- / Lao Tse /
[ccp4bb] Twinned P62
Some time ago, I had a dataset which turned out to be P31 with a dimer sitting on the three-fold axis. The only way I found to process it was to run twinned refinement in CNS with (-h,-k,l) and twinning fraction of 0.5. R/Rfree are 20/24% at 2.4A resolution, so the model must be right at least to some extent. Good news is that I can figure out the dimer, the bad news is that ligand binding site is not quite interpretable (it was missing a loop in MR model and I can't build it from the density I get). So my question is: what is the right way (if any) to improve maps in such a case? Of course, it's quite possible that the aforementioned loop is simply disordered in which case nothing can be done, I presume. Thanks for your help. -- Edwin Pozharski, PhD, Assistant Professor University of Maryland, Baltimore -- When the Way is forgotten duty and justice appear; Then knowledge and wisdom are born along with hypocrisy. When harmonious relationships dissolve then respect and devotion arise; When a nation falls to chaos then loyalty and patriotism are born. -- / Lao Tse /
[ccp4bb] LSQKAB error
Dear all, I am trying to compare several related structures using LSQKAB. In order to refine the superpositions, I'd like to use the option radius, to see the relative postion of certain residues within a given distance from a common point. The programme reads the commands OK: ALL ATOMS MORE THAN 30.000 ANGSTROMS FROM REFERENCE POINT 46.520 37.890 40.280 EXCLUDED as well as the fixed input coordinate file: Logical name: XYZIN2 File name: wtC_on_MnA_SSM.pdb PDB file is being opened on unit 1 for INPUT. No sign of any other file being opened/read, but the following error message is output instead: LSQKAB: ERROR: in XYZADVANCE file has not been opened LSQKAB: ERROR: in XYZADVANCE file has not been opened and the job stops. This happens for both ccp4 versions 6.0.2 and 6.1.1. Is there a working version of the programme somewhere? If not, what other programme could do the same thing (in a simple way...)? Thanks for any suggestions! Anita Anita Lewit-Bentley Unité d'Immunologie Structurale CNRS URA 2185 Département de Biologie Structurale Chimie Institut Pasteur 25 rue du Dr. Roux 75724 Paris cedex 15 FRANCE Tel: 33- (0)1 45 68 88 95 FAX: 33-(0)1 40 61 30 74 email: ale...@pasteur.fr
[ccp4bb] precipitation of deglycosylated protein
Hi everyone, Recently, I obtained a soluble glyco-protein. Unfortunately, after I added PNGase or Endo Hf to remove the glycans, the deglycosylated protein is precipitated. Is there any method to avoid this kind of precipitation? Thanks, Simon
Re: [ccp4bb] precipitation of deglycosylated protein
Hi Simon, Although they are a source of heterogeneity for crystallization, glycosylations usually stabilize proteins. There are a couple of things that may be important to consider before you deglycosylate your protein. Do you know how many natural sequons/glycosylation sites your protein has? And in what system/organism are you expressing your protein? I am saying that because I have the case of a bovine enzyme which has three sites. Inactivation of all sequons from Asn to Asp ( they are standards N-glycosylation sites) and expression in Pichia pastoris results in a fully-deglycosylated protein which is unstable and precipitates. However if one specific sequon is kept intact, the obtained protein is glycosylated by Pichia at this functional site, behaves very well and yields good quality crystals. The electron density maps show the two first N-acetyl glucosamine units N-linked to the Asn residue. Interestingly the protein is pretty homogenously glycosylated by Pichia. I know this may sound a little bizarre but you may get around this problems by keeping some sequons or the sequon active (if there is only one) and try to deal with a protein, glycosylated-light as you express it. This depends on what your expression system is. You can try to add stabilizing agents like glycerol, ethylene glycol or some di-sugars like trehalose. I hope this helps, Cheers, Pascal F. Egea, PhD University of California San Francisco Department of Biochemistry and Biophysics On Mon, Mar 16, 2009 at 9:29 AM, Yue Li simon.yu...@yahoo.com wrote: Hi everyone, Recently, I obtained a soluble glyco-protein. Unfortunately, after I added PNGase or Endo Hf to remove the glycans, the deglycosylated protein is precipitated. Is there any method to avoid this kind of precipitation? Thanks, Simon
Re: [ccp4bb] precipitation of deglycosylated protein
My apologies Simon, I should have been more thorough answering your question. Yes the protein was shown to be quite homogenously glycosylated using mass-spectrometry. The ED maps showed the first two ordered fully occupied NAG units and residual density for a third sugar unit although it is very poor defined. Pascal Egea
Re: [ccp4bb] LSQKAB error
Dear Norman, That did the trick! And was easy to do... Thanks a lot, Anita Dear Anita You could try adding the following additional line of input: rotate matrix 1 0 0 0 1 0 0 0 1 This multiplies the data in XYZINM by the identity matrix (so that the data should be unchanged) but has the side effect of forcing the program to read in the XYZINF input file. Norman From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Anita Lewit-Bentley Sent: 16 March 2009 14:59 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] LSQKAB error Dear all, I am trying to compare several related structures using LSQKAB. In order to refine the superpositions, I'd like to use the option radius, to see the relative postion of certain residues within a given distance from a common point. The programme reads the commands OK: ALL ATOMS MORE THAN 30.000 ANGSTROMS FROM REFERENCE POINT 46.520 37.890 40.280 EXCLUDED as well as the fixed input coordinate file: Logical name: XYZIN2 File name: wtC_on_MnA_SSM.pdb PDB file is being opened on unit 1 for INPUT. No sign of any other file being opened/read, but the following error message is output instead: LSQKAB: ERROR: in XYZADVANCE file has not been opened LSQKAB: ERROR: in XYZADVANCE file has not been opened and the job stops. This happens for both ccp4 versions 6.0.2 and 6.1.1. Is there a working version of the programme somewhere? If not, what other programme could do the same thing (in a simple way...)? Thanks for any suggestions! Anita Anita Lewit-Bentley Unité d'Immunologie Structurale CNRS URA 2185 Département de Biologie Structurale Chimie Institut Pasteur 25 rue du Dr. Roux 75724 Paris cedex 15 FRANCE Tel: 33- (0)1 45 68 88 95 FAX: 33-(0)1 40 61 30 74 email: ale...@pasteur.fr
Re: [ccp4bb] precipitation of deglycosylated protein
Dear Simon, this may be an isolated case, but you might want to try to drastically change the pH of the reaction conditions. In our hands, a protein with 3 hyperglycosylated sites, expressed in Pichia pastoris, could be deglycosylated readily with endoH. However, at the recommended reaction pH (5-5.5), the protein rapidly precipitated in an irreversible manner. After testing the reaction in various different buffers, nearly all of the protein could be deglycosylated at pH 7.5, with no visible precipitation. Curiously, the buffer could easily be exchanged to pH 5.5 and below after the reaction was finished (the protein even crystallized at pH 4). This of course only has a small chance of working in your case, but it's quick to test various different mini-deglycosylation experiments using an array of conditions. Cheers Filip Van Petegem On Mon, Mar 16, 2009 at 9:29 AM, Yue Li simon.yu...@yahoo.com wrote: Hi everyone, Recently, I obtained a soluble glyco-protein. Unfortunately, after I added PNGase or Endo Hf to remove the glycans, the deglycosylated protein is precipitated. Is there any method to avoid this kind of precipitation? Thanks, Simon -- Filip Van Petegem, PhD Assistant Professor The University of British Columbia Dept. of Biochemistry and Molecular Biology 2350 Health Sciences Mall - Rm 2.356 Vancouver, V6T 1Z3 phone: +1 604 827 4267 email: filip.vanpete...@gmail.com http://crg.ubc.ca/VanPetegem/
[ccp4bb] arp/warp ligand
Hi all, I am trying to fit a ligand into density using ARP/wARP 7.0.1 in CCP4 suite 6.0.2 on CCP4interface 1.4.4.2. I get an error message telling me to look for the error in a ##_warp_ligand_details.log. _ Running Refmac5 to refine the protein PDB without the search ligand. After refmac, R = 0.177 (Rfree = 0.000) The difference electron density map has been calculated. Segmentation fault QUITTING ... ARP/wARP module stopped with an error message: MAPREAD_MODE_GRIDMAKER *** Look for error message in the file: 29_warp_ligand_details.log #CCP4I TERMINATION STATUS 0 All done #CCP4I TERMINATION TIME 16 Mar 2009 14:43:30 #CCP4I MESSAGE Task failed *** * Information from CCP4Interface script *** Error during script execution. *** When I look at the details file, all I see at the end is (no error message): ## COORDINATE READING ## Reading apo protein ... done. Identifying N and O atoms for h-bond investigations ... done. Reading clean search ligand(s) ... (PDBfmt) done ___ The details file ends thus, regardless of whether I read in a library file for the ligand or not, the library is one generated from ProDRG or from refmac. Funnily enough, the program ends the same way even using input files that I had used previously, with a previous version of ARP/wARP; input files that worked before. Help, please! Thanks a ton! Sangeetha.
[ccp4bb] Error message while refining protein-DNA complex structure in Refmac5
Dear All I am refining proitein-DNA complex structure in Refamac5. When I used coordinate file containing 2 bases less, then the refinement is running smoth and perfect. But when I built 2 exta bases to the existing DNA in the coot then refinement is failed with the following error message. /usr/local/ccp4-6.1.0/bin/refmac5 XYZIN/usr6/rajkumar/APS/hem/mar9/H2/molrep/BCDNA-built2-NCS-refm2.pdb XYZOUT /tmp/rajkumar/hemCG_19_2_pdb_1.tmp HKLIN /usr6/rajkumar/APS/hem/mar9/H2/molrep/P6122.mtz HKLOUT /tmp/rajkumar/hemCG_19_3_mtz_1.tmp LIBOUT /usr6/rajkumar/APS/hem/mar9/H2/molrep/hemCG_19_lib.cif has failed with error message At line 2486 of file /usr/local/xtal/ccp4-6.1.0/src/refmac5_/make_PDB.f Fortran runtime error: Bad value during floating point read It seems there is error in LIB file generation. Coordinate format and atom labelling is accoring to refmac convention. Please can anybody suggest me how do I trooubleshoot. Thanking you Rajakumara E. Rajakumara Postdoctoral Fellow Strcutural Biology Program Memorial Sloan-Kettering Cancer Center New York-10021 NY 001 212 639 7986 (Lab) 001 917 674 6266 (Mobile) Get your preferred Email name! Now you can @ymail.com and @rocketmail.com. http://mail.promotions.yahoo.com/newdomains/aa/
Re: [ccp4bb] Error message while refining protein-DNA complex structure in Refmac5
Hi Rajkumar, Few days back similar problem was happening to me also. I just changed the version of Coot and it worked. In my case only Coot (ver. 4.1) was doing the job correct. Please try Coot (version 4.1) in case you are using any of other versions. HTH, Y On Mon, Mar 16, 2009 at 11:43 PM, E rajakumar e_rajaku...@yahoo.com wrote: Dear All I am refining proitein-DNA complex structure in Refamac5. When I used coordinate file containing 2 bases less, then the refinement is running smoth and perfect. But when I built 2 exta bases to the existing DNA in the coot then refinement is failed with the following error message. /usr/local/ccp4-6.1.0/bin/refmac5 XYZIN/usr6/rajkumar/APS/hem/mar9/H2/molrep/BCDNA-built2-NCS-refm2.pdb XYZOUT /tmp/rajkumar/hemCG_19_2_pdb_1.tmp HKLIN /usr6/rajkumar/APS/hem/mar9/H2/molrep/P6122.mtz HKLOUT /tmp/rajkumar/hemCG_19_3_mtz_1.tmp LIBOUT /usr6/rajkumar/APS/hem/mar9/H2/molrep/hemCG_19_lib.cif has failed with error message At line 2486 of file /usr/local/xtal/ccp4-6.1.0/src/refmac5_/make_PDB.f Fortran runtime error: Bad value during floating point read It seems there is error in LIB file generation. Coordinate format and atom labelling is accoring to refmac convention. Please can anybody suggest me how do I trooubleshoot. Thanking you Rajakumara E. Rajakumara Postdoctoral Fellow Strcutural Biology Program Memorial Sloan-Kettering Cancer Center New York-10021 NY 001 212 639 7986 (Lab) 001 917 674 6266 (Mobile) Get your preferred Email name! Now you can @ymail.com and @rocketmail.com. http://mail.promotions.yahoo.com/newdomains/aa/ -- * Present Address: Yusuf Akhter, DAAD Fellow EMBL Hamburg c/o DESY, Notkestraße 85, 22603 Hamburg, Germany Mobile: +49-17676339706
