Re: [ccp4bb] metal ion coordination

2014-04-18 Thread Jrh
Dear Faisal, When scrutinising such distances do be aware of the possibility of false precision in the estimates; see eg http://dx.doi.org/10.1107/S2052252513031485 Best wishes, John Prof John R Helliwell DSc On 17 Apr 2014, at 21:13, Faisal Tarique faisaltari...@gmail.com wrote: Dear

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Kay Diederichs
Hi Roberto, for my taste the answers so far have not mentioned (or I did not understand them) that there is a distinction between indicators of the precision of merged data, and those for the precision of unmerged data. It is not possible to directly compare (or equate) indicators of one

[ccp4bb] ligand occupancy

2014-04-18 Thread Monica Mittal
Dear all I have a protein which is dimer having one ligand binding site in each monomer. I refined the crystal structure with ligand in both sites finally. I refined will full occupancy of 1 for ligands (same in both). But now i want to see is there any difference in the occupancy of both ligands

Re: [ccp4bb] Validation reports for all X-ray structures in the PDB

2014-04-18 Thread Gerard DVD Kleywegt
Bonjour Philippe, The reports are based on the recommendations of the wwPDB X-ray validation task force - see http://www.wwpdb.org/workshop/2011/index.html and the report published by this task force at http://www.cell.com/structure/abstract/S0969-2126%2811%2900285-1 Of course, if you have

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Bernhard Rupp
[There is] a distinction between indicators of the precision of merged data, and those for the precision of unmerged data. Let's take a step back - definitions matter: (i) We have multiple observations of the same, already integrated h: the 'unmerged' data - most important data set which

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Kay Diederichs
On Fri, 18 Apr 2014 12:33:30 +0200, Bernhard Rupp hofkristall...@gmail.com wrote: [There is] a distinction between indicators of the precision of merged data, and those for the precision of unmerged data. Let's take a step back - definitions matter: (i) We have multiple observations of the

[ccp4bb] observed criterion sigma

2014-04-18 Thread Faisal Tarique
Dear all I request you please tell me what is the value of Observed criterion sigma (F) and Observed criterion sigma (I) for any data processed by imosflm and scala ? -- Regards Faisal School of Life Sciences JNU

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Bernhard Rupp
(i) We have multiple observations of the same, already integrated h: the 'unmerged' data - most important data set which SHOULD BE deposited and rarely is. yes, fully agree. Perfect. I don't quite understand the difference between (ii) and (iii). As soon as you take the weighted average,

Re: [ccp4bb] ligand occupancy

2014-04-18 Thread George Kontopidis
Hi Monica, Calculate the mean B-factor of all atoms that making interactions with each ligand in monomer A and B. Use those means values as B-factors for each ligand respectively. Adjust manually the occupancies, in order the B-factors for each ligand to stay after refinement close to

Re: [ccp4bb] ligand occupancy

2014-04-18 Thread Boaz Shaanan
Hi Monica, You can refine the ligand occupancy in refmac as explained here: http://www2.mrc-lmb.cam.ac.uk/groups/murshudov/content/refmac/refmac_keywords.html or in phenix, whichever program you're using. Cheers, Boaz Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Edward A. Berry
Roberto Battistutta wrote: Hi, in the Rupp book the following relation is reported (on pag 415): Rmerge ≈ 0.8/I/σ(I) referring to a relation of the linear merging R-value with the signal-to-noise ratio. in a 2006 CCP4bb, Manfred Weiss reported: Rrim (or Rmeas) = 0.8*sd(i)/I Bernhard Rupp

Re: [ccp4bb] Rmerge, Rmeas, I/sigma, Mn(I/sd)

2014-04-18 Thread Kay Diederichs
Hi Ed, your example seems to be designed to show that the average of reciprocal values is not the same as the reciprocal of an average value? If that is what you are alluding to, then please not that the (relatively narrow) Wilson distribution of intensities has the effect of making the

Re: [ccp4bb] crystallographic confusion

2014-04-18 Thread Lavie, Arnon
Dear Kay. Arguably, the resolution of a structure is the most important number to look at; it is definitely the first to be examined, and often the only one examined by non-structural biologists. Since this number conveys so much concerning the quality/reliability of the the structure, it is not

Re: [ccp4bb] crystallographic confusion

2014-04-18 Thread Dale Tronrud
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I see no problem with saying that the model was refined against every spot on the detector that the data reduction program said was observed (and I realize there is argument about this) but declare that the resolution of the model is a number

Re: [ccp4bb] crystallographic confusion

2014-04-18 Thread William G. Scott
Dear Arnon et al: My understanding of the Shannon/Nyquist sampling theorem is admittedly extremely rudimentary, but I think aliasing can result if an arbitrary brick-wall resolution cut-off to the data is applied. So let’s say there are real data are to 2.0 Å resolution. Applying the 2.2 Å