September 2017 - Chimera-users - RBVI Mailing Lists

Time evolution of the crossing angle between helices during MD trajectories
by George Tzotzos 27 Sep '17

27 Sep '17

In Chimera’s Structure Measurement tool, for a given protein, clicking on the Define axes gives the Cartesian coordinates of the centre of each helix as well as its direction. Selecting two helices (say helix 5 and 6) gives the angle and distance between these helices. I take it that the distance is defined as that between the centroids of the centre of mass of the two helices. The question is whether it is possible to work out the time evolution of the crossing angle between to helices during an MD trajectory. MD Movie/Analysis/Plots/Angles plots the angle between three atoms rather than the crossing angle of the chosen helices. Am I right? Missing something? Thanks in advance for your help George

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Re: [Chimera-users] Calculating AreaSES/AreaSAS without a molecular surface?
by Tom Goddard 27 Sep '17

27 Sep '17

Hi Oliver, ChimeraX does not yet have coloring by atom attributes and the “measures sasa” command isn’t saving a per-atom attribute. But you could tweak the code a bit and get the values in the bfactor column of a PDB file. For instance, I added two lines to the ChimeraX Python code for measure sasa in file ChimeraX.app/Contents/lib/python3.6/site-packages/chimerax/core/commands/measure_sasa.py after line 32 areas = spheres_surface_area(atoms.scene_coords, r) add two lines that set the atom bfactor areas = spheres_surface_area(atoms.scene_coords, r) for a, ar in zip(atoms, areas): a.bfactor = ar Then use the command “save areabfactors.pdb” to get those area values in the bfactor column. Some day we will putting the Chimera rangecolor command into ChimeraX so coloring and measure sasa will set an atom attribute enabling the coloring in ChimeraX without code tweaks. Tom > On Sep 27, 2017, at 11:42 AM, Oliver Clarke wrote: > > Hi Tom, > > Thanks! But ChimeraX doesn’t assign it as a per-residue attribute, or am I missing something? > > Is there any way to write out that parameter in ChimeraX per residue or atom, e.g. by replacing the B-factor column? > > Cheers > Oli > >> On Sep 27, 2017, at 2:37 PM, Tom Goddard wrote: >> >> Hi Oliver, >> >> The Chimera solvent accessible and solvent excluded surface area calculations are done by the MSMS surface calculation code, so if it fails you cannot get those numbers. The secret “grid” option in Chimera does not allow computing areas. >> >> ChimeraX computes the areas analytically (command “measure sasa”) and does not create a surfaces (and the ChimeraX surface calculation never fails). >> >> Tom >> >> >>> On Sep 27, 2017, at 11:20 AM, Oliver Clarke wrote: >>> >>> Hi, >>> >>> Is it possible to calculate the areaSES/areaSAS attributes without a molecular surface? For most large complexes, it is only possible to calculate surfaces using the `grid option` (because msms fails), but this does not automatically generate the SES/SAS attributes. >>> >>> Cheers >>> Oli >>> _______________________________________________ >>> Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu >>> Manage subscription: http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users >>> >> > >

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Calculating AreaSES/AreaSAS without a molecular surface?
by Oliver Clarke 27 Sep '17

27 Sep '17

Hi, Is it possible to calculate the areaSES/areaSAS attributes without a molecular surface? For most large complexes, it is only possible to calculate surfaces using the `grid option` (because msms fails), but this does not automatically generate the SES/SAS attributes. Cheers Oli

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High Sierra
by Eric Pettersen 26 Sep '17

26 Sep '17

If you rely on Chimera for your work, you should avoid upgrading to Mac OS X 10.13 (High Sierra) for now. The interfaces that also show OpenGL 3D graphics (Rapid Access/main window; Side View) don’t work correctly. We are working on a fix/patch, but are uncertain how long it will take to develop one. ChimeraX works fine on High Sierra. —Eric Eric Pettersen UCSF Computer Graphics Lab

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Chimera scripting question
by Oliver Clarke 26 Sep '17

26 Sep '17

Hi, I’d like to do the following (presumably with a python script): For each pair of Calphas in two identical structures A and B: Get list of other Calphas within distance cutoff of Calpha(0) for each conformation (say 10 Å); For each Calpha in list: Calc distance difference diff_dist between Calpha(0—>A), Calpha(0—>B) average(diff_dist) over list and assign to attribute So more or less, I think I need to (1) iterate through all Calphas of the first structure (this part I get); (2) check if there is an equivalent Calpha in the second structure (same residue number and chain I guess?); (3) get a list of nearby Calphas, merged between structures (not exactly sure about this but I think I found something in an example I can adapt) (4) calculate distances, then difference-distances between the paired structures, from each target Calpha; (5) assign the averaged difference distance to an attribute (I think I can figure out this bit) Any suggestions much appreciated (or if anyone can point me towards similar scripts I can adapt the would also be most welcome!) The intent of this is to generate an attribute representing local structural flexibility (independent of displacement) - to capture changes in the local arrangements of atoms, decoupled from rigid displacements of domains. The idea is this may be useful for highlighting hinge regions and regions that have undergone plastic deformation, without pre-aligning structures. Cheers Oli

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get near/far clip positions?
by Oliver Clarke 25 Sep '17

25 Sep '17

Hi, I would like to write a script to progressively go through the current scene in n depth steps, saving an image with depth cueing off at each step. I want to do this so I can manually apply depth cueing and DoF effects in post processing. For example, if the near and far clip position are at 0 and 100, and I want to split the scene into 4 depth slabs, I’d like to take images with (near,far)=(0,25),(25,50),(50,75),(75,100). Is there any way in the scripting interface to get the positions of the global clipping planes, so I can calculate how thick each slab should be? Cheers Oli Script (example pseudocode): scene tmp save set depth cueing off depth_steps=4 near_clip=0 (would like to get this position from current scene) far_clip=100 (would like to get this position from current scene) thickness=far_clip-near_clip thickness_per_step=thickness/depth_steps set far clipping plane to (near_clip+thickness_per_step) for i in range (1,depth_steps+1): save image_%i section thickness_per_step scene tmp reset.

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Re: [Chimera-users] Do you recieve image submissions?
by Elaine Meng 25 Sep '17

25 Sep '17

Hi Frank, Sorry for the slow response. I didn’t see your question from last week in my mailbox (might have gone to spam) but now I see it in the archive: <http://plato.cgl.ucsf.edu/pipermail/chimera-users/2017-September/013892.html> No, we don’t really have the manpower to put up other people’s images on the Chimera website currently (given other work demands), although we enjoy seeing them! However, this post mentions some biology-related image contests that may be of interest: <http://plato.cgl.ucsf.edu/pipermail/chimera-users/2017-September/013918.html> Best, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

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Re: [Chimera-users] STL File export size
by Tyrwhitt-Drake, James (NIH/NIAID) [C] 25 Sep '17

25 Sep '17

Hi Joe and David If you want to reduce the mesh density of a Chimera model before export, use the following two methods. These are much more elegant than mesh reduction after export, which can introduce errors. You can read our molecular 3D printing protocol in JoVE for detailed instructions of model generation and printing: https://www.jove.com/video/55427/3d-printing-of-biomolecular-models-for-res… https://www.jove.com/files/ftp_upload/55427/Manuscript_Supplement_material.… Ribbon models * Open Tools>depiction>ribbon style editor * Select the ‘cross section’ tab * Change the ribbon cross section to something simpler. You may draw a square, octagon or (a good balance) hexadecagon. Drawing the shapes can be a little tricky, but the results are worth it! [cid:image003.jpg@01D33385.D40FF980] Surfaces * Instead of using the surface command from the menus, enter the following command in the command line” where ‘#0’ is the model number, and ‘0.5’ is the grid resolution in angstroms. Higher grid values give less detailed meshes * surf #0 grid 0.5 Regards, James Tyrwhitt-Drake Scientific Visualization Specialist Contractor, Medical Science and Computing, Inc. Bioinformatics and Computational Biosciences Branch (BCBB) NIH/NIAID/OD/OSMO/OCICB Building 31, 3B62 Bethesda, MD 240-593-7508 @NIAIDBioIT<https://twitter.com/niaidbioit> | @NIH3Dprint<https://twitter.com/nih3dprint> Disclaimer: The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives. From: Hurt, Darrell (NIH/NIAID) [E] Sent: Friday, September 22, 2017 6:48 AM To: Healey, Joe <J.R.J.Healey(a)warwick.ac.uk>; David Bhella <David.Bhella(a)glasgow.ac.uk> Cc: NIH 3D Print Exchange <3Dprint(a)nih.gov> Subject: Re: [Chimera-users] STL File export size Hi Joe and David, I encourage you to consider the NIH 3D Print Exchange (cc’d) as a place to easily create 3D-printable models of proteins of any size or complexity. We use Chimera as part of our toolchain, so the models will look familiar to you. Check out the “Submit” function of the website to upload a PDB file and get a model in return. Or simply type in a PDB accession code for your model in the “Quick Submit” box to generate a model. https://3dprint.nih.gov Full disclosure: I lead the team that maintains the Exchange. Cheers, Darrell -- Darrell Hurt, Ph.D. Chief, Bioinformatics and Computational Biosciences Branch (BCBB) OCICB/OSMO/OD/NIAID/NIH 5601 Fishers Lane, 4A50 North Bethesda, MD 20852 Office: 240-669-2741 Mobile: 301-758-3559 Web: BCBB Home Page<http://www.niaid.nih.gov/about/organization/odoffices/omo/ocicb/Pages/bcbb.…> Twitter: @niaidbioit<https://twitter.com/niaidbioit> , @NIH3Dprint<https://twitter.com/nih3dprint> Disclaimer: The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives. From: "Healey, Joe" <J.R.J.Healey(a)warwick.ac.uk<mailto:J.R.J.Healey@warwick.ac.uk>> Date: Friday, September 22, 2017 at 6:40 AM To: David Bhella <David.Bhella(a)glasgow.ac.uk<mailto:David.Bhella@glasgow.ac.uk>> Cc: "chimera-users(a)cgl.ucsf.edu<mailto:chimera-users@cgl.ucsf.edu>" <chimera-users(a)cgl.ucsf.edu<mailto:chimera-users@cgl.ucsf.edu>> Subject: Re: [Chimera-users] STL File export size Hi David, Thanks very much! I'm currently experimenting with MeshMixer's "Reduce" to do the same kind of thing - though I think that will only get me so far. I'll certainly have a look at that walkthrough though. I have just realised part of my problem however, was that I was exporting the surface and ribbon representations though without realising it, rather than just the surface, which would be totally redundant when printed. Joe M.Sc. B.Sc. (Hons) MSRB PhD Student MOAC CDT, Senate House University of Warwick Coventry CV47AL Mob: +44 (0) 7536 042620 | Email: J.R.J.Healey(a)warwick.ac.uk<mailto:J.R.J.Healey@warwick.ac.uk> Jointly working in: Waterfield Lab<http://www2.warwick.ac.uk/fac/med/research/tsm/microinfect/staff/waterfield…> (WMS Microbiology and Infection Unit) and the Gibson Lab<http://www2.warwick.ac.uk/fac/sci/chemistry/research/gibson/gibsongroup/> (Warwick Chemistry) Twitter: @JRJHealey<https://twitter.com/JRJHealey> | Website: MOAC Page<http://www2.warwick.ac.uk/fac/sci/moac/people/students/2013/joseph_healey> | ORCID: orcid.org/0000-0002-9569-6738 ________________________________ From: David Bhella <David.Bhella(a)glasgow.ac.uk<mailto:David.Bhella@glasgow.ac.uk>> Sent: 22 September 2017 11:24:55 To: Healey, Joe Cc: chimera-users(a)cgl.ucsf.edu<mailto:chimera-users@cgl.ucsf.edu> Subject: Re: [Chimera-users] STL File export size The free software package meshlab is very effective at reducing the complexity of 3D scenes for printing. There is a tutorial here: https://www.shapeways.com/tutorials/polygon_reduction_with_meshlab D. Dr David Bhella Director - Scottish Macromolecular Imaging Centre MRC-University of Glasgow Centre for Virus Research Sir Michael Stoker Building Garscube Campus 464 Bearsden Road Glasgow G61 1QH Scotland (UK) Telephone: 0141-330-3685 Skype: d.bhella Virus structure group on Facebook: https://www.facebook.com/CVRstructure Molecular Machines - Images from Virus Research: http://www.molecularmachines.org.uk CVR website: http://www.cvr.ac.uk CVR on Facebook: https://www.facebook.com/centreforvirusresearch > On 22 Sep 2017, at 10:38, Healey, Joe <J.R.J.Healey(a)warwick.ac.uk<mailto:J.R.J.Healey@warwick.ac.uk>> wrote: > > Hi Chimera team, > > I'm dealing with some protein structures that vary quite a lot in size. I'd like to make 3D printable versions, so I'm exporting STL files. > > Is there any way to reduce the file size of the exported STLs? How might one control the level of detail (triangulation) of the exported file - I suspect the defaults are including a lot of detail that a 3D printer wouldn't even be able to replicate in the first place. > > Many thanks > > Joe Healey > > > M.Sc. B.Sc. (Hons) MSRB > PhD Student > MOAC CDT, Senate House > University of Warwick > Coventry > CV47AL > Mob: +44 (0) 7536 042620 | Email: J.R.J.Healey(a)warwick.ac.uk<mailto:J.R.J.Healey@warwick.ac.uk> > > Jointly working in: > Waterfield Lab (WMS Microbiology and Infection Unit) > and the Gibson Lab (Warwick Chemistry) > > Twitter: @JRJHealey | Website: MOAC Page | ORCID: orcid.org/0000-0002-9569-6738 > _______________________________________________ > Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu<mailto:Chimera-users@cgl.ucsf.edu> > Manage subscription: http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users

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Contests?
by ginn4711 25 Sep '17

25 Sep '17

Are there contests for chimera images? Sent from my MetroPCS 4G LTE Android Device

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Swapping models in an open structure
by Healey, Joe 22 Sep '17

22 Sep '17

Hi again Chimera Team, I have a large macromolecular structure, and I want to, at random, substitute some of the separate models for a variant form. Is it possible to do this through chimera, e.g. via python? It seems to me it would basically be a case of: 1. enumerate the list of open models 2. pick a model at random 3. either open a new model, fit it to that model, then close the old one, or somehow get the old models co-ords, close it, then open the new one in its place from a specified file path Any alternative suggestions if there's a better way to do this would be great as well. Thanks Joe Healey M.Sc. B.Sc. (Hons) MSRB PhD Student MOAC CDT, Senate House University of Warwick Coventry CV47AL Mob: +44 (0) 7536 042620 | Email: J.R.J.Healey(a)warwick.ac.uk Jointly working in: Waterfield Lab<http://www2.warwick.ac.uk/fac/med/research/tsm/microinfect/staff/waterfield…> (WMS Microbiology and Infection Unit) and the Gibson Lab<http://www2.warwick.ac.uk/fac/sci/chemistry/research/gibson/gibsongroup/> (Warwick Chemistry) Twitter: @JRJHealey<https://twitter.com/JRJHealey> | Website: MOAC Page<http://www2.warwick.ac.uk/fac/sci/moac/people/students/2013/joseph_healey> | ORCID: orcid.org/0000-0002-9569-6738

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Chimera-users September 2017