February 2018 - Chimera-users - RBVI Mailing Lists

areaSAS calculation intuition detail
by Daniel Ziemianowicz 21 Feb '18

21 Feb '18

Hello, I have read as much as I can about SASA calculations but I'm still missing something. I've been enlightened on the difference between solvent-excluded surface (SES) and solvent-accessible (SAS) - particularly from this post: http://plato.cgl.ucsf.edu/pipermail/chimera-users/2010-September/005532.html >From my understanding, the SES is calculated via the 'rolling sphere' method, where the radius of the probe contacts the VDW surface of individual atoms. This used to be my understanding of SAS, as other descriptions have explained it this way, but I now realize this is incorrect. The SES is also what is shown when one enables the surface representation. Now, I read the description of how SAS is calculated at: https://www.cgl.ucsf.edu/chimera/data/sasa-nov2013/sasa.html which more or less makes sense to me. Basically, the radius of the probe is the 'limit of what is seen' from the perspective of the probe center when it overlaps with the VDW of molecule atoms. In this regard, is it true that the SAS probe 'penetrates' the SES surface representation, so greater probe radii observe a greater SAS, with respect to residues. Conversely, larger probe radii observe a reduced SES, with respect to residues. This is my understanding based on my calculations in Chimera. The missing intuition is that I do not understand what the 'limit of penetration', so to speak, is for the SAS probe. E.g. given a protein and its surface, is the probe center limited by the surface but it's radius penetrates/overlaps the surface and the residues within? There must be some sort of limit for the probe center, I imagine, otherwise it would penetrate within the protein molecule and 'see' everything. I hope my question and explanations are clear. It's rather difficult to describe without a visual aid. Regards, Dan Z P.S. these sort of calculations are a dream with Chimera!

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Blast web service appears to be down
by Anitha 16 Feb '18

16 Feb '18

Hi Blast web services and modeller web services are down for the past week. I was able to rectify modeller by opting to run locally Is there any similar options for Blast services? Regards Anitha.S

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Surface selections
by Healey, Joe 16 Feb '18

16 Feb '18

Hi Chimera team, A quick and easy question I hope, is there a shorthand command I can use to select all surfaces? I've tried: sel surf all sel surf sel ,s and some other variations. If this is possible, I'm sure it's simple but I'm just not quite getting there? 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 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 user advice
by Wil Ratzan 15 Feb '18

15 Feb '18

Hello, I truly appreciate the development and distribution of software such as Chimera to the scientific community, but alas I am not 'computer-savvy.' I would like to map highly conserved residues of a protein onto its crystal structure (PDB 3V0I). I can view the PDB file of the crystal structure using Chimera, but I am having a hard time figuring out how to highlight residues. Could you please give me some advice about how to identify and mark particular residues using this file? I apologize if this request seems trivial, and I appreciate any advice. Thanks, -Wil Ratzan Dept. of Cell Biology and Neuroscience Montana State University Bozeman, MT 59717

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Re: [Chimera-users] Analysis of the protein-protein binding interphaces in MARTINI models
by James Starlight 14 Feb '18

14 Feb '18

Thank you so much for the suggestions, Elaine! Indeed, I have turned off the both flags but the intra-models contacts are still recognized. it seems that in order to determine carefully the per-residual contacts between monomers, I should to make a backmapping of the CG models to AA. James 2017-11-27 9:23 GMT+01:00 <sdimicco(a)unisa.it>: > Grazie mille > > > Il 2017-11-23 04:47 James Starlight ha scritto: > > Thank you for the suggestions, Elaine ! > > I have already tried "Find Clashes/Contacts" plugin. In generally, it > works good, however its application on more complex oligomeric > patterns (e.g if I deal with 10-20 GPCRs in one system) is a bit > complicated. Briefly, if I select only one monomer and than try to > find its contacts with the rest of the atoms ( I have changed the > contact threshold to -1.2 for the MARTINI) - it works fine. However, > If I selected all of the atoms (even excluding inter-residue and > inter-molecular contacts) and changing the search criterium "against > themselves" - it found alot of contacts within the monomers. Does > anybody use any tricks for the MARTINI models to fascilitate the > contact searching? > > > James > > 2017-11-22 17:52 GMT+01:00 Elaine Meng <meng(a)cgl.ucsf.edu>: > > Dear James / Gleb, > This question seems too broad, perhaps. I don't know that much about > MARTINI, so I'm guessing instead of atoms you just have a bunch of points > that each represent multiple atoms. In that case you could probably use any > analysis that does not directly use exact atomic locations, atomic radii, or > atomic point charges. Analyses that DO use those things include > surface-area calculations, Find Clashes/Contacts, FindHBond. > > Maybe you should just first think about what Chimera analysis you want to > use, then just try it on your GC model and see if it works rather than > trying to get some exhaustive list of what might work. > I hope this helps, > Elaine > ----- > Elaine C. Meng, Ph.D. > UCSF Chimera(X) team > Department of Pharmaceutical Chemistry > University of California, San Francisco > > On Nov 22, 2017, at 2:23 AM, James Starlight <jmsstarlight(a)gmail.com> wrote: > > Dear Chimera users! > > I would like to make some analysis of the protein-protein binding > established in coarse-grained MARTINI simulations. Briefly Chimera has > recognized a coarse-grained pdb file of 16 martini models of GPCRs. > What Chimera tools (e.g. contact maps, clustering of interphaces) > should work with CG models? What tricks should be used to make this > analysis easier? Because I am working with several proteins in one > system, I would like to work with its CG models without the conversion > to all atomistic representations. > > I thank you so much for the help! > James > > > _______________________________________________ > 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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Video issues
by Mark Warren 14 Feb '18

14 Feb '18

Hi, Running win10 and using Chimera 1.12. Upon startup I'm getting the splash logo, then the rapid access screen. All OK so far. However I load any protein and the dialog along the bottom status bar confirms its loaded but the screen still shows the rapid access screen. I can toggle the lightning button in the bottom right as much as I like but it remains on the rapid access screen. Any ideas what to check? Thanks The Medicines Discovery Catapult is one of a network of elite technology and innovation centres established by Innovate UK as a long-term investment in the UK's economic capability. Applying business-led research, Catapults help businesses transform great ideas into valuable products and services to compete in the global markets of tomorrow. Medicines Discovery Catapult is a company limited by guarantee, registered in England and Wales with company number 09928547. Our registered office is at Medicines Discovery Catapult, Mereside, Alderley Park, Alderley Edge, Cheshire, SK10 4TG. This email and any attachments may contain confidential information and is intended solely for the addressee. If you have received it in error, please send it back to us and immediately and permanently destroy all copies. Do not use, copy or disclose the information contained in this message or in any attachment.

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Feature to remove default bond between hydrogen atoms of water while loading MD trajectory
by NARINDER Kaur Harika 13 Feb '18

13 Feb '18

Dear Sir/Ma'am, I hope you are doing good. I am interested in making MD movie from AMBER trajectory in chimera 1.12 version. Unfortunately when I load prmtop and mdcrd files in MD movie, it shows default bond between hydrogens of water molecule. I dont want to show this bond while presenting my research at meetings so I would be really grateful if I can get any help regarding removing this unwanted bond in water molecules. For further clarity I have attached avi movie file of small section of my trajectory. Thank you very much for your help and support. With Regards, Narinder Kaur Harika Georgia state university

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TM tendency hydrophobicity scale
by Shyam Saladi 13 Feb '18

13 Feb '18

Hi all -- I have put together a Chimera attribute definitions to color residues according to the TM tendency hydrophobicity scale: Zhao and London, Protein Sci 15:8 (2006), doi: 10.1110/ps.062286306 An amino acid "transmembrane tendency" scale that approaches the theoretical limit to accuracy for prediction of transmembrane helices: relationship to biological hydrophobicity In case it's helpful to others, it's attached to this message. Perhaps the Chimera team would also be interested in including it with the other scales <https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/hydrophob.html> online as well. Thanks, Shyam -- Shyam Saladi <http://shyam.saladi.org> NSF Graduate Research Fellow Biochemistry and Molecular Biophysics California Institute of Technology

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Errno 13
by Dustin Park 13 Feb '18

13 Feb '18

Hello, After using docking preparation and run, I set the executable location to vina and clicked ok. However, the result is that there is a chimera error ([errno 13] Permission denied. Can you explain to me how to get past the docking preparation step and why this error is coming up? Not sure how else to do this step. Thank you.

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Pipes command deletes the previous pipes model
by vamsee 12 Feb '18

12 Feb '18

Hello Elaine, I'm trying to create pipes models with different edge colors for 2 models. I use the following command for the first model (model # - 0.11). *pipes #0.11 helixArrow false helixSplit false helixSplitRatio 7.0 helixEdgeColor blue* Then I try to create the second pipes model using the same command with the model number changed (model number #0.12) *pipes #0.12 helixArrow false helixSplit false helixSplitRatio 7.0 helixEdgeColor red* Basically the difference between the two pipes models is the edge color. But, when I run the second command, it deletes the first pipes model (#0.11). I'm not sure what is going on. I'm attaching the whole code here. Please advise. *open 0 4G80.pdb* *split* *delete #0.1-10* *focus* *color white,r #* *pipes #0.11 helixArrow false helixSplit false helixSplitRatio 7.0 helixEdgeColor blue* *pipes #0.12 helixArrow false helixSplit false helixSplitRatio 7.0 helixEdgeColor blue* Thank you, Vamsee

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