Re: [ccp4bb] Alternate sugar conformations in refmac 5.5.0110

2013-04-19 Thread Thomas Lütteke
Hi Markus, I had a brief look at the structure fragment that you had included in your mail, and I don't think that you really observe these two conformations. Stereochemistry of the A conformation looks fine, but the sugar in the alternate B conformation is not an NAG but an NDG (i.e. it has

Re: [ccp4bb] Alternate sugar conformations in refmac 5.5.0110

2013-04-19 Thread Herman . Schreuder
Dear Markus, I just did a test: I generated in Coot an alternative conformation for an ASN with attached NAG, wrote out the coordinates and manually adapted the LINK record, read it back in in Coot and hit the Refmac button (version 5.7.0029). Except for some green difference density because I

[ccp4bb] OT: Funded PhD at University of Leicester, UK and Institut Laue-Langevin Grenoble, France

2013-04-19 Thread Peter Moody
I should be most grateful if you could point your most able students who might be considering a PhD to one of the following links. http://www2.le.ac.uk/departments/biochemistry/postgraduate-study/Three-year%20PhD%20programme.doc or

[ccp4bb] Postdoc position in protein structural modeling and EM image data analysis

2013-04-19 Thread Gunnar Schroeder
Postdoc position in protein structural modeling and EM image data analysis We have an opening for a Postdoc position in the Computational Structural Biology Group (www.schroderlab.org) at the Forschungszentrum Jülich, Germany. Our group is working on modeling and refinement of protein

Re: [ccp4bb] Alternate sugar conformations in refmac 5.5.0110

2013-04-19 Thread Dom Bellini
Dear Markus, You could also try the inse keyword, which will tell refmac two mutually exclude two atoms occupying the same position but we occupancy for example of 0.6 and 0.4, stopping them from repelling each other. Here is an example in the case of an Fe site which was contaminated by Mn in

[ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Peter Artymiuk
Dear all In Britain there is a free newspaper that you can pick up on buses called the Metro. My colleague Geoff Ford pointed out this short feature on the history X-ray crystallography in last Monday's Metro newspaper. I think it's rather good.

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread David Briggs
Following on from that - readers may be interested in Stephen Curry's post in the Guardian, regarding the Crystallography exhibit at the London Science Museum. http://www.guardian.co.uk/science/occams-corner/2013/apr/19/1 regards, Dave David C. Briggs PhD

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Peter Artymiuk
Another of my colleagues, Jeremy Craven, is an NMR spectroscopist and bioinformatician. He is in referee mode at present and comments: From: Jeremy Craven c.j.cra...@sheffield.ac.uk Date: 19 April 2013 10:05:18 GMT+01:00 To: Peter Artymiuk p.artym...@sheffield.ac.uk Subject: Re: Fwd:

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Navdeep Sidhu
Dear Pet, On the contrary, far as I know, nature seems to require most solids we see around us to be crystalline. And much of the rest is either gaseous or plasma. Hence, by the reasoning proposed, we are led to suspect a different conclusion: that it's studies dealing with the remaining state

[ccp4bb] Simple swingout centrifuge for screening plates?

2013-04-19 Thread Eckhard Hofmann
Hi all, we are looking for a new swingout centrifuge to spin down drops in case our nanodispensing is not perfectly centered. Ideally it should have small footprint and low price. The simple PCR-centrifuges (2 slots, vertical) don't work, at least in our hands. The standard swingout

[ccp4bb] Refinement with anomalous signal

2013-04-19 Thread Kavyashree Manjunath
Dear users, The native structure for a protein is available and there is a ligand bound data. The crystallisation condition has anomalous scattering metal ions (Cd). Both the data are scaled by separating anomalous pairs. So while refining a ligand bound data with a solution obtained using

Re: [ccp4bb] Refinement with anomalous signal

2013-04-19 Thread Kavyashree Manjunath
Sir, Thank you Sir. I tried this once at the end in order to check the refinement statistics, R, Rfree and FOM showed improvement. but I encountered one problem. One of the a nomalous scatters which had double occupancies (which was confirmed by anomalous peak search) after the refinement of

Re: [ccp4bb] Refinement with anomalous signal

2013-04-19 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Dear Kavya, one reason could be an incorrect script for running refmac, or a bug in refmac, or, if the distance allows, that the two peaks really are two different fully occupied atoms with a lesser anomalous signal than expected. Best, Tim On

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Peter Artymiuk
Just to clarify, Jeremy was not being serious, but imagining what an awkward / obnoxious grant reviewer might have said in 1913. But your points would be valuable in rebutting such a view Pete On 19 Apr 2013, at 11:28, Navdeep Sidhu wrote: Dear Pet, On the contrary, far as I know,

Re: [ccp4bb] Refinement with anomalous signal

2013-04-19 Thread Kavyashree Manjunath
Dear Sir, Thank you. I run refmac using GUI so most Probably there are two different atoms. Regards Kavya -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Dear Kavya, one reason could be an incorrect script for running refmac, or a bug in refmac, or, if the distance allows, that the two

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Bernhard Rupp (Hofkristallrat a.D.)
However, a reviewer could reject the method on theoretical grounds - the explanation of X-ray diffraction as a multi-photon process is not correct BR -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Peter Artymiuk Sent: Friday, April 19, 2013

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hello Bernhard, could you explain this? A photon is the exchange particle of the electromagnetic force, i.e. as soon as you have more than two charged particles interacting there is more than one photon - why is it incorrect to use the term

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread James Holton
Because there is never more than one photon in flight at any given time. Even at 1 photon/s, we still eventually get spots. Atoms also don't emit synchrotron radiation, despite there being charged particles accelerating around their little orbits in there. But yes, in 1913, people were

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Bernhard Rupp (Hofkristallrat a.D.)
Simply on grounds that even a single photon can get diffracted (remember the photon counting multiwire detectors?). The phenomenon might be best described as something like a annihilation-creation process a la Feynman. Much of this has been discussed on board before. Mini-summary: 'Multiphoton'

[ccp4bb] Postdoctoral Position at Imperial College London

2013-04-19 Thread P Freemont
Imperial College London Department of Life Sciences Faculty of Natural Sciences Research Associate Salary range: £32,100 - £40,720 per annum We wish to recruit a Research Associate to work in the research group of Professor Paul Freemont (www.msf.bio.ic.ac.uk), in the Department of Life

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Colin Nave
James In 1915, I thought Debye and Scherrer were testing for interference between the electrons in different orbits within atoms. This was in order to test the Bohr model. They got rings but they were powder diffraction rings. The method never did identify planetary type orbitals. However

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread Dom Bellini
I would like to add/support James comments. Once it used to bother me the fact that diffraction was observed from the crystal even though the beam does not possess a space-time coherence (or even worse in the case of in-house diffractometers). This is because in text books they always

[ccp4bb] Alternate sugar conformations in refmac 5.5.0110

2013-04-19 Thread Markus Meier
Problem Solved - Short Summary --- Dear all, First of all, a big thank you to everyone who devoted their precious time to help figure this out! Good news, Refmac (tested with v.5.7.0032) does handle alternate sugar conformations correctly. As Thomas Lütteke

Re: [ccp4bb] popular piece on X-ray crystallography

2013-04-19 Thread James Holton
It was the observation that atoms have size. Rutherford's alpha-particle experiment had shown that the nucleus was incredibly small, very much smaller than the distances between atoms, bringing about the solar system idea, which right away came into question because such atoms would produce