[ccp4bb] Postdoctoral position at the European Institute of Oncology, Milano

2013-10-15 Thread Marina Mapelli
Postdoctoral research position in Structural Biology of Asymmetric Cell Division A postdoctoral research position is available in the group of Marina Mapelli at the European Institute of Oncology in Milano. The main interest of the group focuses on the molecular mechanisms underlying

[ccp4bb] Staining Crystals with comassie

2013-10-15 Thread Swastik Phulera
Dear All, I am looking for a method to quickly differentiate between salt and protein crystals. I have been told thats its a popular alternative to the commercially available izit dye. I would appreciate if some one would share their comassie crystal staining protocol. Swastik

Re: [ccp4bb] Staining Crystals with comassie

2013-10-15 Thread Zhijie Li
Izit is an aqueous solution of methylene blue, which you can prepare simply and cheaply. Look here: http://www.ysbl.york.ac.uk/ccp4bb/2000/msg00387.html One word of warning: not every crystal stains. I found poking crystal with hair or glass fibre to see if it cracks or breaks is more

Re: [ccp4bb] High Rsyms between 5-7 A

2013-10-15 Thread Kay Diederichs
Hi Ursula, if you look at the Wilson plot, you see a minimum near 6A resolution. This means that in the range 7-5A, intensities are low, and Rsyms are therefore elevated. best, Kay On Mon, 14 Oct 2013 11:52:03 -0700, Ursula Schulze-Gahmen uschulze-gah...@lbl.gov wrote: Here is some more

[ccp4bb] Molrep and Refmac5 errors

2013-10-15 Thread Rajiv K Bedi
Dear all, I recently started using CCP4i (Windows 8) software for data processing and model building but I get the following error messages whenever I use molrep and refmac5: MOLREP #CCP4I TERMINATION STATUS 0 MOLREP(ccp4): Error in label assignments in LABIN #CCP4I TERMINATION TIME 08 Oct

[ccp4bb] POSTDOC POSITION at UC Irvine, SoCal

2013-10-15 Thread Hudel Luecke
Immediate opening for a postdoc in structure-based drug discovery on any of these projects: 1) inhibitor discovery against the Helicobacter pylori acid-gated urea channel (ulcers, stomach cancer) 2) reactivation of p53 cancer mutants 3) inhibitors inosine monophosphate dehydrogenase (anti-P.

[ccp4bb] CCP4 Study weekend 2014

2013-10-15 Thread Cooper, Jon
CCP4 Study weekend 2014 on Complementary Techniques - programme now live at: http://www.cse.scitech.ac.uk/events/CCP4_2014/programme.html What techniques can be combined with crystallographic analysis? Of all deposited structures in the PDB, more than half are oligomeric, and three quarters

[ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Yarrow Madrona
Hello crystallography experts, I think I may have a case of perfect pseudomerehedral twinning where P222 Laue symmetry is actually P2 with twinning and aniostropic data masks intensity based twinning statistics. I would like some input to determine if my reasoning makes sense. I would like to

[ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Yarrow Madrona
Hello crystallography experts, I think I may have a case of perfect pseudomerehedral twinning where P222 Laue symmetry is actually P2 with twinning and aniostropic data masks intensity based twinning statistics. I would like some input to determine if my reasoning makes sense. I would like to

[ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Yarrow Madrona
Hello crystallography experts, I think I may have a case of perfect pseudomerehedral twinning where P222 Laue symmetry is actually P2 with twinning and aniostropic data masks intensity based twinning statistics. I would like some input to determine if my reasoning makes sense. I would like to

Re: [ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Phil Jeffrey
Hello Yarrow, Since you have a refined molecular replacement solution I recommend using that rather than global intensity statistics. Obviously if you solve in P21 and it's really P212121 you should have twice the number of molecules in the asymmetric unit and one half of the P21 asymmetric

Re: [ccp4bb] High Rsyms between 5-7 A

2013-10-15 Thread Ursula Schulze-Gahmen
Thanks for all the great suggestions. They included beamline problems, detector-specific problems, translational NCS, narrow dynamic range problem for strong low resolution reflections,radiation damage, and more. The agreement seems to be that no matter what the reason for the high Rsym is, it is

Re: [ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Yarrow Madrona
Hi Phil, Thanks for your help. I ran a Find-NCS routine in the phenix package. It came up with what I pasted below: I am assuming the the first rotation matrix is just the identity. I need to read more to understand rotation matrices but I think the second one should have only a single -1 to

Re: [ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Dale Tronrud
Since Phil is no doubt in bed, I'll answer the easier part. Your second matrix is nearly the equivalent position (x,-y,-z). This is a two-fold rotation about the x axis. You also have a translation of about 31 A along x so if your A cell edge is about 62 A you have a 2_1 screw. Dale Tronrud

Re: [ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Yarrow Madrona
Thank you Dale, I will hit-the-books to better the rotation matrices. I am concluding from all of this that the space group is indeed P212121. So I still wonder why I have some outliers in the intensity stats for the two additional screw axis and why R and Rfree both drop by 5% when I apply a

Re: [ccp4bb] A case of perfect pseudomerehedral twinning?

2013-10-15 Thread Dale Tronrud
R factors cannot be used to detect twining. The traditional R is calculated using structure factors (roughly the square root of intensity) but you can't do that calculation in the presence of twining because each structure factor contributes to two intensities. The formula for the R in the

[ccp4bb] Methods to detect/distinguish carbohydrates, lipids, proteins and nucleic acids

2013-10-15 Thread Hua Yuan
Dear CCP4 members: Sorry for the off-topic subject, but I'd appreciate it if you could share your experience with methods that could easily detect or distinguish carbohydrates, proteins, lipids and nucleic acids. The story began with a 2D gel of a sample from IP. Instead of seeing different