Re: [ccp4bb] outliers

2022-11-08 Thread Dale Tronrud
The second part of your question has to do with assessing the probability of correctness of a model by comparing the distribution of the individual values of geometry items with the distribution observed in large sets of high quality crystal structures. Certainly, if your model has many

Re: [ccp4bb] outliers

2022-11-08 Thread Kay Diederichs
On Tue, 8 Nov 2022 15:25:03 -0800, James Holton wrote: >Thank you Ian for your quick response! > >I suppose what I'm really trying to do is put a p-value on the >"geometry" of a given PDB file.  As in: what are the odds the deviations >from ideality of this model are due to chance? > >I am

Re: [ccp4bb] outliers

2022-11-08 Thread Dale Tronrud
Let's say you have decided that you want to know if the CA-CB bond of residue 123 in your favorite protein differs from the expected value for that type of bond. You solve the structure and refine a model against your crystallographic data, then look at residue's 123 CA-CB bond and find

Re: [ccp4bb] outliers

2022-11-08 Thread Petr Kolenko
Dear James, I hope I will not disturb this thread and you will further continue with the theoretical aspects. But, what is the motivation for such a general question? In my crystal structures, I usually have many bonds outside the 3-sigma interval. Especially in the case of ligands. And not

[ccp4bb] Research Fellow position in Singapore

2022-11-08 Thread hans song
We are seeking two enthusiastic and self-motivated postdoctoral research fellows. One candidate will work on Hippo signalling pathway and drug design and the other candidate will work on developing circular RNA as the second generation vaccine. Requirements: · PhD in biochemistry,

[ccp4bb] Mini map aide updates

2022-11-08 Thread Jon Cooper
For info, or more likely amusement, the Mini Map Aide website which I put together a few months ago for looking at electron density maps, primarily on mobile devices: http://minimapai.de now allows tweaks to be made to individual amino acids and basic regularisation to be done, so there

[ccp4bb] Postdoc position at Duke University

2022-11-08 Thread Seok-Yong Lee
Dear all, We are recruiting a postdoc. A NIH-funded post-doctoral research position is available in the laboratory of Seok-Yong Lee at the Duke University School of Medicine to study the structural and mechanistic basis of membrane transport processes. The lab’s current research focuses on three

Re: [ccp4bb] outliers

2022-11-08 Thread James Holton
Thank you for this. Hmmm. Interesting, and good to know the expected distribution of extreme values. However, what I'm more worried about is how to evaluate the other 999 points?  Lets say I'm trying to compare two 1000-member sets (A and B) that both have an extreme value of 3, but for the

Re: [ccp4bb] outliers

2022-11-08 Thread Petrus Zwart
Hi James, This is what you need. https://en.wikipedia.org/wiki/Generalized_extreme_value_distribution The distribution of a maximum of 1k random variates looks like this, and the (fitted by eye) analytical distribution associated with it seems to have a decent fit - as expected. [image:

Re: [ccp4bb] outliers

2022-11-08 Thread James Holton
Thank you Ian for your quick response! I suppose what I'm really trying to do is put a p-value on the "geometry" of a given PDB file.  As in: what are the odds the deviations from ideality of this model are due to chance? I am leaning toward the need to take all the deviations in the

Re: [ccp4bb] [EXTERNAL] [ccp4bb] outliers

2022-11-08 Thread Dias, Joao M.
Hi James, My initial thought is that a 3-sigma bond length deviation is significant. When we make an experiment and observe something that doesn’t correspond to what we expect, it could be an error, or it could be that we found the thread for a new discovery. If the experimental data supports

Re: [ccp4bb] outliers

2022-11-08 Thread Ian Tickle
Hi James I don't think it's meaningful to ask whether the deviation of a single bond length (or anything else that's single) from its expected value is significant, since as you say there's always some finite probability that it occurred purely by chance. Statistics can only meaningfully be

[ccp4bb] outliers

2022-11-08 Thread James Holton
OK, so lets suppose there is this bond in your structure that is stretched a bit.  Is that for real? Or just a random fluke?  Let's say for example its a CA-CB bond that is supposed to be 1.529 A long, but in your model its 1.579 A.  This is 0.05 A too long. Doesn't seem like much, right? But

[ccp4bb] Postdoc Opening in X-ray, Cryo-EM, cell biology, at Princeton

2022-11-08 Thread Alexei Korennykh
A postdoctoral or more senior researcher opportunity is available immediately in the laboratory of Alexei Korennykh in the Department of Molecular Biology at Princeton University. We invite candidates with relevant PhD degrees to work in the fields of human cell biology and structural biology.

Re: [ccp4bb] Optimising a Nanobody interface computationally to improve binding

2022-11-08 Thread Jonathan Elegheert
Hello, Indeed, Rosetta-ddG can evaluate the effect of residue mutations. Also, have a look at the program FoldX for per-residue evaluation of mutations (https://foldxsuite.crg.eu/). Then, there is the freeware webtool FireProt, its algorithm uses FoldX as a pre-filter to select beneficial

[ccp4bb] Optimising a Nanobody interface computationally to improve binding

2022-11-08 Thread Jonas Emsley
Dear all I have a protein engineering question. If you have a nanobody ligand complex structure is there a program that can use the crystal structure to suggest engineering improvements to give a tighter binding nanobody. It need not just be in the CDRs. Maybe rosetta can do this? Any