December 2021 - ChimeraX-users - RBVI Mailing Lists

ViewDockX for Autodock Vina error
by Visvaldas K. 13 Dec '21

13 Dec '21

Dear colleagues, for some reason ChimeraX does not recognize pdbqt from Autodock Vina 1.1.2 as a "docking file", even though it opens pdbqt file just fine (The message: No suitable models found for ViewDockX). The documentation says that Autodock Vina is supported. Perhaps it's the version of Vina (I use 1.1.2, or preferably its fork Smina, while the newest version is 1.2)? If I knew what the file that ChimeraX recognizes as a "model" looks like, I'd write a script to reformat my pdbqt, but at the moment I'm in the dark... Not too bad since I still can view the structures, but perhaps I'm missing some cool features... Thank you in advance, Vis

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Save ribbons and surfaces with minimal amount of vertices/faces
by Sarah Piper 13 Dec '21

13 Dec '21

Hi ChimeraX team and others, I got a bit of an unusual question and am interested to see whether it is possible! I am trying to use a short helix in ribbon style from ChimeraX into Blender, and use it to create a 'skeleton' for animations. For this, it would be most useful to have as few vertices as possible for the helix (basically only the 'invisible' coordinates themselves as 'line', instead of having it as a 3D view/thick helix. When I export a helix even with a very thin ribbon style through the command line (e.g. width and thickness to 0.1), this is unfortunately still too thick and creates too many vertices/faces. Setting these values to 0 gives errors. I have looked at the ribbon style editor in Chimera as well, and unfortunately the minimum settings are 0.05. Would it be possible to somehow set any of these parameters to 0 and save this as a file format suitable for 3D softwares (e.g. .glb)? Would it work through a python script potentially? (I'm not familiar with python in chimera yet but happy to learn more about this). And if so, would this be also applicable for surfaces, to reduce the numbers of vertices/faces that are exported? On another note, I was wondering whether it would be possible to set the chimaera scene 'world origin' to a particular coordinate set; I think in Pymol this is possible with resetting the camera view: cmd.set_view([ 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 40.0, 100.0, -20.0]) Sorry for these unusual question but looking forward to hearing back from anyone who might have any suggestions! Cheers, Sarah

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Showing long coiled coil alpha helices as tubes
by Huiskonen, Juha T 13 Dec '21

13 Dec '21

Hi all, I am trying to render two long alpha helices forming a coiled coil as tubes instead of ribbons. The tubes rendered with default settings do not however follow the paths of the helices. Instead, the tubes become almost straight. Any suggestions? Best wishes, Juha

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rotation parameters of the map
by Dmitry Semchonok 13 Dec '21

13 Dec '21

Dear colleagues, When I align one map to the other (either manually or by using the Fit option), I would like to know the applied rotation parameters. How to find them our when a) using just Fit option b) rotation manually and then using the Fit option? Thank you Sincerely, Dmitry

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Question about chimeraX installization.
by 박시훈 11 Dec '21

11 Dec '21

Dear chimeraX users, I want to change the installation folder of chimeaX in linux (centos7.0). The default folder is user/bin however, I want to install chemeraX in the other folder because of my computer environments (the Master and Slave nodes do not share the usr/bin folder). Can I know how to change the installation folder? Best regards Si Hoon Park

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1.3 release
by Eric Pettersen 10 Dec '21

10 Dec '21

UCSF ChimeraX version 1.3 has been released! Updates since version 1.2 (May 2021) include: - AlphaFold tool and command to get AI-predicted protein structures - Selection Inspector to inspect/change attributes of atoms, bonds, etc. - Scale Bar tool and command - new BLAST Protein GUI with easier controls for showing hit info such as source species, crystallographic resolution, ligands in structure - Altloc Explorer tool and command to switch among alternate locations - model loops and missing segments with Modeller - combine or copy models - change bond lengths - apply command files iteratively to multiple input files - list multiple map-fitting solutions from global search For more details, see the ChimeraX change log: https://www.rbvi.ucsf.edu/trac/ChimeraX/wiki/ChangeLog <https://www.rbvi.ucsf.edu/trac/ChimeraX/wiki/ChangeLog> Enjoy! --Eric

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re-sampled map (volume resample #X onGrid #Y) difference with general mrc map
by Dmitry Semchonok 10 Dec '21

10 Dec '21

Dear colleagues, I have an issue with the output map re-sampled from the resampling step protocol. Could you please explain how different the re-sampled map is compared to the general mrc map (without rotation manipulations)? Because it seems that some important information is missing or/changed in the re-sampled.mrc Kind regards, Dmitry

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Re: [chimerax-users] alphafold predict multiuser syntax
by Tom Goddard 09 Dec '21

09 Dec '21

Hi Jerry, It is unlikely you will be able to get AlphaFold to predict multimers composed of multiple 1000 amino acid proteins even with the most powerful GPUs available. The EBI AlphaFold database produced by Google predicted structures of up to 2700 amino acids. From the paper that was done by combining the memory of 4 GPUs (which cannot be done on Colab), that might be 64 Gbytes. The GPU memory use of AlphaFold is said to be quadratic in number of residues. When I last tested with Google Colab GPUs with 16 Gbytes a few months ago it failed with 1000 amino acids. But that was AlphaFold 2.0 and now we are using AlphaFold 2.1. It would require testing, but it is very likely that 1500 total amino acids in a complex will run out of memory, and quite possibly 1000 will run out of memory when your GPU has only 16 Gbytes. This is one of the limitations of AlphaFold, and of the old Google Colab GPUs with only 16 Gbytes. The AlphaFold database has predictions for human proteins larger than 2700 amino acids made by breaking into 1400 amino acid chunks and computed at intervals of 200 amino acids. Then you can attempt to piece together those chunks. I give an example of that piecing together in ChimeraX here https://rbvi.github.io/chimerax-recipes/big_alphafold/bigalpha.html Tom > On Dec 9, 2021, at 10:12 AM, Jerry Honts <jerry.honts(a)drake.edu> wrote: > > Unfortunately several of the proteins I’m studying are ~1000 amino acids and the evidence is they form multimers. So I was wondering if Colab Pro + would actually succeed, or whether this is currently not a feasible solution. > > I should mention that I have students use Chimera in several of my courses to solve problems (and they like it), and I hope to move students to ChimeraX this year. So thanks for maintaining and refining this wonderful software. > > Jerry

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Re: [chimerax-users] alphafold predict multiuser syntax
by Tom Goddard 09 Dec '21

09 Dec '21

Hi Jerry, I have not tried Colab Pro+ which is $50 per month and claims to give faster GPUs, more memory, longer session times. I use Colab Pro which is $10 per month because the free Colab was sometimes not letting me run jobs more than 2 hours per day. https://colab.research.google.com/signup The main factor for running larger predictions (e.g. > 1000 amino acids) is GPU memory. With Colab Pro Google never gave me a GPU with more than 16 GBytes -- I get old Nvidia T4, P100 and K80 GPUs just like with free Colab. At UCSF I can run AlphaFold (not in ChimeraX) using new Nvidia A40 or A100 GPUs which have 48, 40 or 80 GBytes but I have not tested on large proteins to see how large. The runs on 800 amino acid predictions are about 2 to 3 times faster on these new GPUs. Tom > On Dec 9, 2021, at 9:44 AM, Jerry Honts <jerry.honts(a)drake.edu> wrote: > > Hi Tom: > > Many thanks for your quick reply! I so appreciate AlphaFold access being built into ChimeraX—it has already resulted in several interesting leads. > > As a second question if I may ask: would upgrading the Google Collab Pro + help with AlphaFold predictions? Any experience with this? > > Jerry

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alphafold predict multiuser syntax
by Jerry Honts 09 Dec '21

09 Dec '21

I am trying to use the AlphaFold predict multimer function in ChimeraX 1.3 with this syntax like (comma-separated pasted sequences): alphafold predict MPEHPIQLASSNQVVSQILTTTQGSPTRQSKTFVYRSE,MSESPIRSSQYGKHVVNVSHIEKGQAPIYVSQSTVQNPIYVEKIVKVESSNT But I keep getting an error: Missing or invalid "sequence" argument: Sequences argument "MPEHPIQLASSNQVVSQILTTTQGSPTRQSKTFVYRSE,MSESPIRSSQYGKHVVNVSHIEKGQAPIYVSQSTVQNPIYVEKIVKVESSNT” is not a chain specifier, alignment id, UniProt id, or sequence characters I think I am following the syntax given in the online help file, but can you suggest a reason for this error? Single chain predictions have been working fine with pasted sequences. Thanks, Jerry E. Honts Drake University

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