Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-17 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Pavel, maybe I should have explained in better detail to avoid confusion. The importance of the contribution to the X-ray term from hydrogens has been well-known (and used in refinement programs) for - I guess - more than 40 years, but I am sure

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-16 Thread Tim Gruene
Dear Jeff, I would assume that clashing hydrogen atoms beome less and less an issue with current refinement programs, since those I am familiar with (refmac5 and phenix) both genereate constrained hydrogen atoms by default now, and it has been like this for quite some time - so the situation

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-16 Thread Pavel Afonine
Hi Tim, just to spice your words up with some numbers You may also want to note that constrained hydrogen positions are a crude approximation and only work with X-ray data where hydrogen atoms have little impact on the data. This contribution can be as large as 1.5% difference in

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-16 Thread Jeffrey Bell
Hi, Tim, When we were working on our paper in 2011, refmac had a bug that always indicated in depostions that riding hydrogens were used, whether they were or not. Published methods did not always clarify this issue. Since we could not be definitive, we refrained from saying too much about it.

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-15 Thread Jeffrey Bell
Hi, all, I am glad to see these matters being discussed.  I think we all believe that protein crystallographers should be concerned with producing models that modelers and chemists can respect and use.  Schrödinger spends a lot of time thinking about ligands; its refinement program, PrimeX,

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-13 Thread Ute Krengel
From: CCP4 bulletin board CCP4BB@JISCMAIL.AC.UK on behalf of Tom Peat tom.p...@csiro.au Sent: 13 June 2014 09:08 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem I’ll wade into this quagmire before the weekend starts

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-13 Thread Frank von Delft
board CCP4BB@JISCMAIL.AC.UK on behalf of Tom Peat tom.p...@csiro.au *Sent:* 13 June 2014 09:08 *To:* CCP4BB@JISCMAIL.AC.UK *Subject:* Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem I’ll wade into this quagmire before the weekend starts. There are without question some dodgy structures

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-13 Thread Tim Gruene
Hi Ethan, Maybe I miss something, but whenever an error in one of the cif-files has been reported, be it directly to Garib, or publicly on the ccp4bb, Garib (I assume) fixed very quickly - I don't quite understand why we need a new term for this process? Best, Tim On 06/12/2014 10:45 PM, Ethan

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-13 Thread Engin Özkan
Do those fixes also make it to the phenix version of the library? Yes, this is the CCP4bb, but the monomer library is also used by Phenix, and a good number of structures (almost half of those deposited this year?) in the PDB now come from phenix.refine. Or in other words, is there a central,

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-13 Thread Ethan Merritt
On Friday, 13 June 2014 10:12:50 AM Tim Gruene wrote: Hi Ethan, Maybe I miss something, but whenever an error in one of the cif-files has been reported, be it directly to Garib, or publicly on the ccp4bb, Garib (I assume) fixed very quickly - I don't quite understand why we need a new term

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-12 Thread Jeffrey Bell
Hi, Tim, Thanks for your comment. Do you agree with the editorial's claim that some 25% of the deposited protein-ligand complexes might be dodgy in significant details?  This editorial comment represents something that I often hear from drug discovery professionals. Is it a matter of PR

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-12 Thread Tim Gruene
Hi Jeff, there are quite a few implications in your brief email that each might open a long thread of discussion. As brief as possible I think one has to be a good scientist and a good crystallographier to fully understand the meaning of a crystal structure, and I think many people believe a

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-12 Thread Joel Tyndall
@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem Hi Jeff, there are quite a few implications in your brief email that each might open a long thread of discussion. As brief as possible I think one has to be a good scientist and a good crystallographier to fully understand

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-12 Thread Ethan A Merritt
. This is also an option assuming the data has been deposited. My two cents J -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Tim Gruene Sent: Friday, 13 June 2014 5:54 a.m. To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Hosed-Up X-Ray Structures

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-12 Thread Joel Tyndall
: Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem On Thursday, 12 June, 2014 20:24:43 Joel Tyndall wrote: Hi, I saw Jeffs post with interest and have held off until now. It is relatively easy to find structures with bad geometry for small molecules but it does not do any good simply

[ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-10 Thread Jeffrey Bell
An editorial comment about protein crystallography appeared under that title. It's short and worth considering. http://pipeline.corante.com/

Re: [ccp4bb] Hosed-Up X-Ray Structures: A Big Problem

2014-06-10 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I hope that the contents of this section is obvious to most readers of the ccp4 bulletin board. Cheer, Tim On 06/10/2014 03:40 PM, Jeffrey Bell wrote: An editorial comment about protein crystallography appeared under that title. It's short and