October 2019 - Chimera-users - RBVI Mailing Lists

Bond-type error
by Laia Ferrer Duran 14 Oct '19

14 Oct '19

Hi, I recently started using chimera for one project from university. At first I worked in the university computer that it had the program. Today, as I have to work from home I downloaded the latest version of chimera in the web page and I tried to do a dock prep in the protein from DB 2am9. With the receptor it worked well, but when I done it with the ligand TES it seems to have a problem with the add charges fase. I searched first in all you webs and all it seems to say is that the molecular structure isn't correct but I really think there isn't a problem with the structure because with exactly the same steps it used to work in the university computer. The error says: (TES) sh: 1: C:/Program: not found (TES) /usr/bin/antechamber: Fatal Error! (TES) Cannot properly run "C:/Program Files/Chimera 1.14rc/bin/amber18/bin/bondtype -j part -i ANTECHAMBER_BOND_TYPE.AC0 -o ANTECHAMBER_BOND_TYPE.AC -f ac". Failure running ANTECHAMBER for residue TES Check reply log for details I don't know if it could be some problem with my program or if I should change the configuration of the program or what it is that isn't working. Thanks in advanced and I look forward you answer.

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surface color
by Schmid, Michael F. 14 Oct '19

14 Oct '19

I’m trying to do the same thing as Chimera’s “Surface Color”, but in ChimeraX, on the command line. After reading the docs, I tried “color height #1 (the map designation) center 0,0,0 axis z rainbow”. It gave “expected a keyword”. What did I miss? Thanks, Mike

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FAD binding site on Cryptochrome
by Margiotta, Joseph 11 Oct '19

11 Oct '19

Hi-> I am very new to molecular modeling and have a very basic novice user issue. We are studying cryptochrome proteins some of which are known to bind the chromophore Flavin adenine dinucleotide (FAD) and for this and other reasons are considered photopigments. We have looked at a cryptochrome in chicken that binds FAD and is light sensitive (GallusCRY4) and have sent the AA sequence to Zhang’s COACH site for Protein-ligand binding site prediction (https://zhanglab.ccmb.med.umich.edu/COACH/) at the University of Michigan. The results come up with a C-score confidence prediction of 0.59 with a cluster size of 63 for FAD binding to GallusCRY4. The results allow you to download the 3D model and the residue-specific binding probability, which is estimated by SVM, the predicted bound ligands and detailed prediction summary, and the templates clustering results. We’d now like to extend this modeling to GallusCRY1 and GallusCRY2 to see get a FAD binding prediction and the complex structure with the most representative ligand in the cluster. The COACH site lets you export the model and complex structure in PDB format and I downloaded Chimera to visualize and analyze the PDB results. I would like to be able to label the structures using the binding probabilities, and template clustering results to include the predicted FAD binding pocket on the three CRY proteins and also label a tetrad of Trp residues that are thought to be responsible for electron transfer. Can you give me some general guidance on how to start this analysis? -- Joseph F. Margiotta, PhD Professor of Neurosciences UT College of Medicine & Life Sciences Block HS 120A Mail Stop 1007 Toledo, OH 43614 419-383-4119

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Centroid/axis question
by Luca Pellegrini 08 Oct '19

08 Oct '19

Hello, I have generated a bunch of axes and centroids for my protein complex structure. Now I would like to change their appearance by changing their radius, to make them the size I want for a picture. Is there a way to do this for an existing axis/centroid, or do I need to create them again? I have got quite a lot of them… Thanks, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge Cambridge CB2 1GA United Kingdom lp212(a)cam.ac.uk tel.: 0044 1223 760469 https://www.bioc.cam.ac.uk/pellegrini-group/pellegrini-group @PellegriniLab

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Question about electron density map
by Zhang, Bixia 04 Oct '19

04 Oct '19

Dear Developer, I want to have a figure of my ligand only and its electron density, and I used my protein mtz file to generate a CCD4 map in phenix and then open in chimera. I tried fit in map but it does not fit well. Could you please help me out? And after I have the electron density, how to hide the backbone electron density? Thanks a lot! Best, Bixia

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next/previous buttons suggestion
by Oliver Clarke 04 Oct '19

04 Oct '19

Hi, I like and frequently use the next/previous buttons (present in the daily builds) for sequential model display or activation. They are very useful for quickly comparing multiple 3D classes, or multiple aligned atomic models. One thing that would make this feature even more useful would be the capacity to lock display of a model - that is, temporarily remove it from the next/previous sequence. This would be useful, for example, when one wants to keep a single “reference” atomic model (or density map) displayed, but sequentially compare with multiple other maps/models. Would this be possible to add? Either as a command, or adding another checkbox that controls the lock/unlock status of the currently displayed model. Cheers Oli

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[ Asking how to combine loops of models after refinement ]
by Hồ Phương Dung 03 Oct '19

03 Oct '19

Dear Sir/Madam, I am Dung. I am currently using Chimera to do the refinement for my protein because it has some large missing residues segments. I use Tools/ Loops- Model refinement of Chimera software to do that task. As it was failed to generate models if I performed refinements for all missing residues segments. Thus, I decided to refine them not at once. The problem is that I could not find how to combine the separated loops from models after refinement. I am new to Chimera so I hope that my description can be useful for you to imagine my problem. I hope that you could support me to solve this problem. I really appreciate it. Thank you for spending your valuable time. Yours sincerely, Dung Hồ Ngọc Phương Dung International University - Vietnam National University Email: phuongdunghongoc(a)gmail.com

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PROBLEM IN ENERGY MINIMIZATION
by Prabuddha Bhattacharya 02 Oct '19

02 Oct '19

Dear Chimera, I have been facing a problem recently while using UCSF Chimera. After opening the structure of ligands in the chimera window as .pdb file, when ever I am trying to minimize the energy (Tools-->Structure Editing-->Minimize Structure) of that ligand in (which is in .pdb form), I am getting the following error message: "Failure running ANTECHAMBER for residue". I am using "AMBER ff14SB" (for standard residues) and "Gasteiger" (for other non-standard residues). Upon trying out with "AM1-BCC" (for other non-standard residues), I am getting an altered compound so that cannot be perhaps tried. Kindly find attached the .pdb files for the ligands I am trying to minimize the energy, and a word file containing the screen shots of the step-by-step messages leading to the error message that I am getting. I will be highly grateful if you can help me in sorting out the problem. Thanks in advance, Best Regards, *Prabuddha Bhattacharya * *Assistant Professor* *Adamas University* *Kolkata 700126* *India*

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Re: [Chimera-users] Selecting residues with zones when reference is absent
by Elaine Meng 02 Oct '19

02 Oct '19

> On Oct 1, 2019, at 11:39 AM, Carlos G. Oliver <cgoliver(a)protonmail.com> wrote: > > Hi Elaine, > I just have a follow-up question on this topic. > Specifically the command: > > select ligand & nucleic acid z<10 > > I'm not sure how the & operator is working here but it seems that it considers the two selections independently and then takes the intersection. > > However it would be faster to first select the ligands and then within the ligand atoms find the ones that satisfy the second condition. > > When I tested it on 6s0z knowing beforehand the name of the residue: > > select #0:ery z<10 > > The computation is much faster. > Wondering if there is a way to more efficiently combine the selection conditions similar to this. > Thanks again! > Best, > Carlos G. Oliver Hi Carlos, Sending questions to chimera-users (CC’d here) is recommended unless involving private data. Others may know the answer when I don’t, and messages may fall through the cracks if you them only to my individual address. I’m not a programmer and don’t know the code structure, so I don’t know if there is any ingenious way of structuring your specification to make it faster. There might not be a way. However, your two commands seem to be doing totally different things. Is ERY the ligand? In that case your second command is lacking the “nucleic acid” part. The documentation says that & has highest priority, <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/atom_spec.html#combi…> … so your second command > select ligand & nucleic acid z<10 > intersects ligand with all residues within 10 angstroms of nucleic acid. is that what you are trying to do, find all ligands within 10 A of nucleic acids? Naturally this is going to take much longer than your first command > select #0:ery z<10 … which just finds all residues within 10 A of ligand ERY. It’s looking at a zone from one residue instead of a zone from many (hundreds?) of nucleic acid residues. The comparison should instead be to select #0:ery & nucleic acid z<10 … which I suspect would be just as slow. There are various ways to split up the selection process but I don’t have any reason to believe that they would be faster. In general, ChimeraX is much faster than Chimera for working with large structures (say ribosome), at least in rendering, and allows using parentheses in command-line specifications so it’s clearer what you will get. In ChimeraX, the command could be something like select ligand & (nucleic :<10) ...which takes 1 second on my laptop with structure 6s0z, whereas Chimera with your first example command is just hanging on that same structure and had to be force-quit. However, maybe ChimeraX doesn’t do all of the other things you are currently trying to do. ChimeraX is available under similar licensing conditions as Chimera (free for noncommercial use): <http://www.rbvi.ucsf.edu/chimerax/index.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

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Gaussian filter prior to fitmap?
by Oliver Clarke 02 Oct '19

02 Oct '19

Hi, Would it be possible to add an option to fitmap (in either/both chimera/chimerax) to restrict the spatial frequencies used for fitting? That is, to fit gaussian filtered versions of the input maps behind the scenes, but apply the resulting transform to the unfiltered maps? Filtering maps to say 15 Å gives a much better radius of convergence in my experience - much less prone to getting stuck in local minima. In general I also wish that when applying a gaussian filter in Chimera (or chimerax), the approximate equivalent in spatial frequency terms was indicated - e.g. if I am applying a gaussian filter of sdev x to a map of pixel size y, what lowpass filter does this effectively equate to? Also, when one wants to fit multiple maps to a single reference (quite common when inspecting results of 3D classification), Chimera gives an error message indicating that multiple maps have been input. There is an “eachmodel true” option one can set to allow fitting of multiple maps to a single reference, but the default value is false. It seems to me that the default value for this should be true, as if the user is specifying a wildcard or model ID range for the maps to fit, this is probably the behavior they are after I think. Or maybe the error message could be altered to indicate that if this is what one wants to do the eachmodel keyword needs to be specified? Cheers Oli

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Chimera-users October 2019