Re: [ccp4bb] X-Ray films

2010-04-19 Thread Eleanor Dodson
Wasnt it the tramp whom they beat to death - and the book was R James.. That movie gave the cold shivers.. eleanor Philip Leonard wrote: I have a vague recollection of a student carrying books about crystallography getting beaten up at the start of Clockwork Orange. This might only be in the

Re: [ccp4bb] Proportion of MR in PDB

2010-04-19 Thread James Holton
Here are my counts of the various methods used for PDBs as of a few days ago: 37851 MR 7802 MAD/SAD NULL 669 OTHER 53 N/A 993 MIR 352 SIRAS 316 MIRAS 188 AB-INITIO 88 SIR 6 RIP 2 UNCONVENTIONAL 1 UNCONVENTIANAL 1 FIBER-DIFFRACTION 56171 TOTAL The other 8605 don't have REM200 entries.

Re: [ccp4bb] Mysterious Crystals?

2010-04-19 Thread Sean Seaver
Perhaps this is a case of a 'phantom crystal' that was discussed on the CCP4bb awhile back: http://bit.ly/b6Rgw7 All the Best, Sean

[ccp4bb] XVII BCA/CCP4 Summer School in Macromolecular Crystallography: closing date for pre-registration 1st May 2010

2010-04-19 Thread Elspeth Garman
Any applicants for this Summer School who have not already done so should pre-register by 1st May 2010, on which date the WWW site will close. As stated on the pre-registration form, applicants will not be considered for a place on the School unless a supporting letter from their supervisor

[ccp4bb] Automated beta-sheet definition for PDB-deposition ?

2010-04-19 Thread Mueller, Juergen-Joachim
Dear depositors, does exist there any program that is able to handle the beta-sheets of complicated structures like beta-helices, bifurcated sheets ... to produce the input for PDB-deposition. The program included in the PDB-deposition procedure failes in our case and there are lots of strands

Re: [ccp4bb] merging Pymol sessions ? Non-CCP4 question

2010-04-19 Thread Jason Vertrees
Jürgen, PyMOL sessions are essentially pickled Python dictionaries. At this point I'm not aware of a way to easily merge the contents of two sessions. This would be a nice new feature; I've added it to my list of features enhancement requests. Thanks, -- Jason On Sun, Apr 18, 2010 at 6:36

Re: [ccp4bb] unable to fly? - Pittsburgh

2010-04-19 Thread Regina Kettering
I would like to extend this to Pittsburgh as well. We are in Eastern Pittsburgh, available by bus or taxi to Pittsburgh International Airport. We have wireless internet but not much apartment space. If you are stuck in Pittsburgh, please send me an email to make arrangements. Regina -

Re: [ccp4bb] Proportion of MR in PDB

2010-04-19 Thread Edward A. Berry
Quite a lot of structures in the PDB involve minor variations on structures that have already been solved (different ligands, mutants, high res), so the solution involves refining the previous structure against the new data, perhaps starting with rigid body refinement to correct minor variations

Re: [ccp4bb] Mysterious Crystals?

2010-04-19 Thread Edward A. Berry
Well, the good news is that they don't seem to be salt crystals. But have you really ruled that out? With small molecule crystals the diffraction pattern is so sparse, and at such high resolution, that you are likely to miss it altogether in a one-degree oscillation and looking for spots around

Re: [ccp4bb] sigma cutoff for fitting waters in model

2010-04-19 Thread Ed Pozharski
I second Tim's opinion. In the days of CNS/O, there was a popular rule to place waters in 3 sigma peaks that make chemical sense, then re-refine and keep those waters that produce more than 1 sigma in 2fo-fc map. (With Coot the default cutoff is 5). There could be a bizarre probabilistic

Re: [ccp4bb] Proportion of MR in PDB

2010-04-19 Thread Ian Tickle
I would say it should still be classed as MR: the distinguishing feature of MR is surely that it uses an known structure as a starting model, not that it does a rotation/translation search. In any case the distinction between a rigid-body search and RB refinement is moot. At Astex our automated

Re: [ccp4bb] Re: [ccp4bb] Mysterious Crystals?

2010-04-19 Thread Ed Pozharski
Couldn't they simply be too thin? After all, unit cell dimensions are routinely about 0.01um, so if these needles are only fraction of a micron thick, there is simply not enough material for diffraction. Nice looking but non-diffracting protein crystals are too disordered (i.e. while packing is

[ccp4bb] Calculation of electron density map for a twinned dataset

2010-04-19 Thread protein.chemist protein.chemist
Hi All, I have a dataset that shows about 50 % twinning. I was curious what will be the best way for the refinement and calculation of electron density maps, including the composite omit map. Thanks a lot. Mariah -- Mariah Jones Department of Biochemistry University of Florida

Re: [ccp4bb] sigma cutoff for fitting waters in model

2010-04-19 Thread Anastassis Perrakis
Hello - The sigma issue a bit more complicated. What we call usually sigma is the root mean square deviation (rmsd) of the map. Lets first recall, that the variation within the protein region is quite large, while the solvent is rather flat. Now, lets take an 'extreme' example, of a

Re: [ccp4bb] Calculation of electron density map for a twinned dataset

2010-04-19 Thread Eleanor Dodson
The newest refmac will deal with this and generate maps with twinning corrected.. Eleanor protein.chemist protein.chemist wrote: Hi All, I have a dataset that shows about 50 % twinning. I was curious what will be the best way for the refinement and calculation of electron density maps,

Re: [ccp4bb] sigma cutoff for fitting waters in model

2010-04-19 Thread Ian Tickle
... or you could just use the RMSD of the difference map (i.e. that using 2(mFo-DFc) coefficients for acentric reflns), which is a reasonable approximation of the uncertainty provided most of the structure is accounted for, as the uncertainty of the Fourier map (i.e. that using 2mFo-DFc for

Re: [ccp4bb] (slightly more on) sigma cutoff for fitting waters in model

2010-04-19 Thread Pavel Afonine
Hello: some more on water picking... After quite a bit of experimenting, I found this working the way I like (implemented in phenix.refine): 1) peak at mFo-DFc map is higher than ~3sigma, and 2) peak center is within a hydrogen bond to another atom (water or macromolecule), and 3) peak has

Re: [ccp4bb] sigma cutoff for fitting waters in model

2010-04-19 Thread Pavel Afonine
Hi Ian, ... or you could just use the RMSD of the difference map (i.e. that using 2(mFo-DFc) coefficients for acentric reflns), which is a reasonable approximation of the uncertainty provided most of the structure is accounted for, as the uncertainty of the Fourier map (i.e. that using 2mFo-DFc

Re: [ccp4bb] sigma cutoff for fitting waters in model

2010-04-19 Thread Ian Tickle
Hi Pavel AFAIK it's not in the literature, in fact I wasn't even aware it was in phenix, but that's probably only because we don't use phenix (sorry! - being commercial we would have to pay for it!). The problem is always where you put little tidbits like this, unless it's part of a much bigger

Re: [ccp4bb] Re: [ccp4bb] Mysterious Crystals?

2010-04-19 Thread Phoebe Rice
Move the beam stop back? My lab has grown quite a few crystals that only diffract to very low resolution. Phoebe (with sympathy!) Original message Date: Mon, 19 Apr 2010 11:35:11 +0800 From: tat cheung cheng theif...@yahoo.com.hk Subject: [ccp4bb] Re: [ccp4bb] Mysterious

[ccp4bb] chiral volumes--losing it

2010-04-19 Thread Patrick Loll
Friends, A question about the definition of chiral volumes: I'm looking for the definition of the SIGN of a chiral volume. The only ccp4 reference I can find (readily) is this: http://www.ysbl.york.ac.uk/~garib/refmac/docs/theory/chiral.html This page gives an algorithm for

[ccp4bb] chiral volumes--2nd try

2010-04-19 Thread Patrick Loll
Sorry, the original post looks garbled (mirroring my internal state, no doubt). I'm trying again, sending as plain text: Friends, A question about the definition of chiral volumes: I'm looking for the definition of the SIGN of a chiral volume. The only ccp4 reference I can find (readily)

Re: [ccp4bb] chiral volumes--2nd try

2010-04-19 Thread Bernhard Rupp
The problem of discrete values in restraints can be circumvented by computing a corresponding continuous value such as a chiral volume Vc, which is given by a scalar triple vector product A • (B x C) originating at the central atom. With the smallest ligand pointed toward the observer and

Re: [ccp4bb] Re: [ccp4bb] Mysterious Crystals?

2010-04-19 Thread Laurie Betts
Dear Cheng, You could take your non-diffracting needle urchins and crush them in their growth solution (vortex several minutes and/or try Hampton seed bead). Then make serial dilutions of the seed solution and add them to a whole new screen (the MMS method) or try the optimization method with

[ccp4bb] how to make cholesterol solution

2010-04-19 Thread Jerry McCully
Dear ALL: Sorry for this kind of off-topic question. I am going to co-crystallize one protein with cholesterol. I read some papers saying that their protein can be pre-incubated with 1mM cholesterol in the presence of 5% (v/v) ethanol. TO do so, I first dissolved cholesterol in