March 2021 - ChimeraX-users - RBVI Mailing Lists

Move model to specific coordinates of reference model
by Vorländer,Matthias Kopano 19 Mar '21

19 Mar '21

Hi there, I am trying to place a model (volume) at specific coordinates of a second volume (the first model is a map and the second model is a tomogram). I have managed to place a sphere at the desired position, but I can’t figure out how do this with a volume file. Example for placing the sphere: shape sphere radius 100 center 5243.80,3103.88,1086.01 coordinateSystem #1 How can I achieve the same but placing a volume at the desired location? Thanks a lot, Best, Matthias

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building peptides in Chimera/ChimeraX
by Elaine Meng 18 Mar '21

18 Mar '21

Hello Ishita, Your question was forwarded. I'm CC'ing chimerax-users(a)cgl.ucsf.edu (which is the recommended address for asking ChimeraX questions, for future reference). Peptide-building in ChimeraX (and Chimera) does not predict the structure, it simply uses whatever angles you choose in the Build Structure tool. So the reason it looks like a helix is that you told it to use the helix phi,psi angles. ChimeraX build structure: <https://rbvi.ucsf.edu/chimerax/docs/user/tools/buildstructure.html#start> In the paper figure, it says that the indolicin structure is PDB 1g89 ... so if you want it to look like that, just open 1g89. In the legend it says structures generated by Chimera, but apparently they just mean that images of the structures (from the PDB) were generated by Chimera. 1g89 is an NMR ensemble of 16 structures, so they apparently just chose one of the structures to show and hid the others. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > -------- Forwarded Message -------- > Subject: Request regarding ChimeraX (From UC Davis) > Date: Wed, 17 Mar 2021 02:04:17 +0000 > From: Ishita M Shah <imshah(a)ucdavis.edu> > > Dear Dr. Ferrin, > I’m a Project Scientist at UC Davis and the newest user of ChimeraX. > I have a few questions regarding peptide secondary structure generation using ChimeraX. Would you please connect me to someone who could spare a few minutes to walk me through? > > Specifically, when I look up the secondary structure of Indolicidin (generated using Chimera) _ image attached from publication (it shows an extended structure), whereas, using Tools -> Structure editing -> Build Structure -> Start Structure -> Peptide/ Input sequence, the image I get is completely different (attached .bmp file). I really have basic requirements of prediction of secondary structures of peptides (and was using Indolicidin as an control) prior to exploring more. > > I apologize if this information regarding the use of ChimeraX for this purpose is readily available and that I could just be unaware of it. Any advice you can offer is highly appreciated. > > Best, > ishita. > > Ishita M. Shah, PhD > Associate Project Scientist > Associate Director, Microbial Programs > Foods for Health Institute > Department of Food Science and Technology > University of California Davis > 1221 Robert Mondavi Institute, South > Davis, CA 95616 > Phone: (530) 754-7962 > > https://ffhi.ucdavis.edu/people/ishita-shah > https://www.linkedin.com/in/ishita-m-shah-ph-d-a6a9664/ >

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Re: [chimerax-users] Global Diffusion Tensor Models
by Tom Goddard 17 Mar '21

17 Mar '21

Hi Arun, I see from the image you sent that the diffusion ellipsoid script I sent you gave the wrong ellipsoid orientation -- it was using the inverse of the rotation. Here is the correct ChimeraX script which I have also put on the ChimeraX Recipes web site: https://rbvi.github.io/chimerax-recipes/ellipsoid/ellipsoid.html <https://rbvi.github.io/chimerax-recipes/ellipsoid/ellipsoid.html> Tom > On Mar 17, 2021, at 12:23 PM, Gupta, Arun <Arun.Gupta(a)warwick.ac.uk> wrote: > > Dear Tom, > > I think this is what you referring w.r.t to orientation. I have also overlaid the ROTDIF generated output " Tensor axes " on the protein PDB in the attached pic. Although, the ellipsoid shape model representation doesn't looks great. > > Best Regards > > Arun >

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How to produce a multiple sequence alignment
by Luca Pellegrini 17 Mar '21

17 Mar '21

Hello, I have superposed several similar structures with Matchmaker, and now would like to obtain a structure-based multiple sequence alignment. In Chimera, Matchmaker has a nice button ‘After superposition, compute structure-based multiple sequence alignment’. ChimeraX produces all pairwise alignments with the reference structure, but how do I obtain a single alignment with all my sequences? Best wishes, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge Cambridge CB2 1GA UK

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Global Diffusion Tensor Models
by Gupta, Arun 17 Mar '21

17 Mar '21

Dear ChimeraX team, I am interested in generating Global diffusion tensor geometry models such as Prolate, Ellipsoid, Oblate or Sphere with overlaid protein PDB or structure of my interest. (As shown in attached pic). I am using diffusion tensor prediction module provided in ROTDIF software (http://gandalf.umd.edu/FushmanLab/pdsw.html) to generate an ellipsoid diffusion tensor of a protein molecule of my interest. Is it possible that I can use ROTDIF generated output (Which is in Pymol output format, please find attached ) to open in ChimeraX with my protein PDB, to render such representative figure ? Thanks!!! Arun Arun Gupta PhD, MRSC Research Fellow Challis & Lewandowski Group Chemistry Department University of Warwick Gibbet Hill Road Coventry CV4 7AL United Kingdom

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Blast Protein not working
by Moradkhan, Tiglath A 16 Mar '21

16 Mar '21

Hi I found what the problem is. I forgot to blast my sequence. But when I run the blastprotein tool I get the following error: ValueError: not enough values to unpack (expected 2, got 1) File "C:\Program Files\ChimeraX 1.1\bin\lib\site-packages\chimerax\blastprotein\pdbinfo.py", line 206, in fetch_info entry, auth_cid = pcid.split('_') See log for complete Python traceback. I would be very grateful for your help. Thank you Tiglath

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Question about modelling
by Moradkhan, Tiglath A 16 Mar '21

16 Mar '21

Hi For some reason when I try to model using ChimeraX it cuts off the first two amino acid residues of the N-terminus. I'm trying to model dimeric sea otter Apo A-I using the pdb structure of 3R2P as a template. The sea otter sequence is: DEPQSPWDRVKDLATVYVDVVKDGGRDYVAQFEASA LGKQLNLKLLDNWDSLSSTVTKLREQIGPVTQEFWDNLEKETEALRQEMSKDLEEVKQKV QPYLDEFQKKWHEEVELYRQKVAPLGAELREGARQKLQELQEKLTPLGEELRDRARTHVD ALRAQLAPYSDQLRERLASRLQALK But the template does not contain the first two amino acid residues. When I model the sea otter protein, it doesn't include the first two amino acids. I'm not sure why it's doing that. I would be very grateful for your help. Thanks Tiglath

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radial coloring cryo map
by Moustafa, Ibrahim M. 15 Mar '21

15 Mar '21

Dear all, I am trying to color a cryoem map radially in ChimeraX (to get something similar to surface color by radius in chimera). I used the following comand: color radial #model However, the map is colored from one side to the other instead of radial coloring starting from the center. I tried to specify the center of the screen as 0,0,0 but that did not help. What is the correct command/options to do radial coloring in ChimeraX? Thanks for help, Ibrahim

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pause/wait read user input in chimerax script
by andrew 13 Mar '21

13 Mar '21

Greetings, I would be grateful for help with a script. I made a .cxc script. Now, I would like to show somebody the steps, one by one as in I download this [return] I select that [return] colour these [return] but I cannot see how to insert a pause/wait or something that waits on keyboard input. I did try to insert a "runscript" and put some lines in a python script that reads from the keyboard, but it looks as if chimerax has redirected the script's stdin. I have a feeling, that if I knew what I was doing, I could put another line in the python script "import chimerax.core" and read until the next newline from the command line. Is there a way to pause after each line in a script ? Many thanks for any advice.

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Placement of markers after translation
by Helge Paternoga 09 Mar '21

09 Mar '21

Dear ChimeraX team, I have a question regarding the placement of markers. I am currently trying to extract densities from cryo-EM maps for figure preparation. Therefore, I am using markers to colour any density that is not part of what I want to extract and then split the map accordingly. I noticed that when I translate a markerset, e. g. by using "view position" with "sameAsModels", new markers are not placed at the cursor position, but instead are transformed according to the translation of the whole markerset. Therefore, to move markers, I have to use the "move marker" command on each marker separately. I would like to know if this behaviour is intented and if it can be switched somehow to place markers at the cursorposition even after translation of the markerset. Ultimately, I would like to re-use defined markersets for extracting (or "cleaning") the same invariant components of my maps. But the current behaviour makes it nearly impossible to add new markers for touch-ups after opening and aligning a markerset. Best, Helge

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