December 2016 - Chimera-users - RBVI Mailing Lists

Multiscale models command
by Ian Holmes 20 Dec '16

20 Dec '16

Hello Chimera gurus, I am using multiscale models to view a virus capsid (PDB 2QA0) in Chimera. I would like to create a Python script to render the capsid as a multiscale model and then highlight (i.e. select) certain residues. However, I can't figure out the command-line syntax to create a multiscale model. The docs also suggest the Midas Python module as an alternative way of scripting Chimera in Python, but I haven't yet found that module. Here is the rough order of what I am doing from the graphical user interface: Open model 2QA0 Tools menu -> Higher-order structure -> Multiscale Models panel (The following actions are all in the Multiscale Models panel) Click "Make models" button in "Models from molecules and matrices" section Click "All" button in "Select chains:" section Click "Hide" button in "Act on selected chains" section, "Selected chains" subsection Click "All" button in "Select chains:" section (again) Select "Ribbon" from "Style" menu in "Act on selected chains" section (then back to the main view) Zoom out (with mouse wheel) Favorites menu -> Command Line Type "select :10,20,30" (amino acids I want to highlight) Here is what I've got so far in terms of equivalent Python code: import os from chimera import runCommand as rc rc("open 2QA0") # make multiscale model here? rc("select :10,20,30") # select some residues Your help would be appreciated - thanks! Ian

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(no subject)
by Kartheek 19 Dec '16

19 Dec '16

Hi UCSF CHIMERA users, I am trying to make a movie in chimera using MD movie and pdb option. However I have been stumbled with the following error "Residue 256.C not in first model on line 20792 of /tmp/tmpvr4a2t.pdb". I do not have any end records, how can I rectify the error ?? -- Sincerely, P.Kartheek, Research Scholar, IIIT-H, Hyderabad, INDIA.

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Surface clip coloring
by Michał Kadlof 16 Dec '16

16 Dec '16

How can color volume by value with binning several values into single color? I achived the effect partialy by opening several times the same map. set different thresholds and colors to each one and playing with Per-Model Clipping tool, but it have some drawbacks. Planes can't be at exact same level because I observe artifacts. So I tried to move slightly inner layers upp, but still I observe "staris" effect. I also tried with Surface color tool, but it uses interpolation and blends colors togather. In other words I need something like this: https://1.bp.blogspot.com/-5B5ueLHCBPY/T4II4IddvwI/AAAAAAAAB_w/rYwqsJNldY0/… instead of something like this: https://i.stack.imgur.com/hQmry.png -- pozdrawiam serdecznie Michał Kadlof <m.kadlof(a)cent.uw.edu.pl>

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probably a bug
by Michał Kadlof 16 Dec '16

16 Dec '16

Hello, I visualize density of my data two different way with the same thresholds and observe different sizes of regions. Isn't it a bug? -- pozdrawiam serdecznie Michał Kadlof <m.kadlof(a)cent.uw.edu.pl>

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Hide side chain
by Zhu, Xiaoyan 12 Dec '16

12 Dec '16

Hello, I am using UCSF Chimera to generate figures of protein crystal structures. Some crystals, if open in Chimera, automatically show the side chains of some amino acids. I want to hide those side chains in my figures. I wonder if there's an easy way to do it. Thank you! Have a good one, Xiaoyan Zhu Ph.D. Candidate Department of Biological Sciences, Marquette University

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Multiple transparent objects
by Daniel Asarnow 12 Dec '16

12 Dec '16

Hi, I'm having some trouble with a movie of a morph between structures of the same protein bound to two different ligands. The basic idea is a closeup of the binding pocket, and as the morph progresses the initial ligand becomes transparent while the second one becomes opaque. The result is a similar effect to crossfade, only the morph animation is playing simultaneously. I've tried both the screen capture and ray tracing methods, with the following results: Screen capture - When a ligand is almost entirely transparent, a white silhouette is shown at the highest z-order, blocking what's behind. - There is a "pop up" effect when the ligands suddenly switch z-order at the beginning and end of my animation. - Single-layer and flat transparency options don't help. Ray tracing - Multiple transparency is fine. - Reflections and shadows are not made transparent. - E.g. when one ligand is 100% transparent, the reflections and shadows are still visible as white lines and dark spots. Maybe someone here has some insights on my transparency problems? A way to use crossfade instead would be even better. I can record movies with the two ligands separately and then crossfade them manually with ffmpeg. However, it would be nice to have this working entirely in chimera, especially for some more complicated animations I have in the works. Best, -da

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.pyc session file
by Luca Pellegrini 12 Dec '16

12 Dec '16

Hi, How can I open in Chimera a saved .pyc session file? When I try, Chimera reports the following error message: Error while processing /Users/lp212/Dropbox/<filename.pyc>: .pyc files are not portable; please use .py file instead Unfortunately I don’t have the .py file, Chimera doesn’t seem to have saved it (not sure why). Thanks, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge 80 Tennis Court Road Cambridge CB2 1GA UK Email: lp212(a)cam.ac.uk Phone: 0044-1223-760469

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Selective lighting
by Oliver Grant 12 Dec '16

12 Dec '16

Hi all, Is it possible to use the lighting command and have it apply only to particular models? I'd like my ligand to "pop" out by having a light that only shines on it, and not the protein. Oliver

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Fit-to-window for procedurally generated images
by Mike Sivley 09 Dec '16

09 Dec '16

I am procedurally generating images of protein structures using a Chimera python script. I can center the protein structure within the viewing window, align the protein to emphasize certain elements, set the output size of the final image, and manually apply a scale factor to the view, but I have not found a way to ensure that the protein structure is maximized (but fully contained) within the final image. Is there a "fit-to-window" command that will automatically scale the view in this way? Thanks! Mike Sivley

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How to find symmetry parameters for icosahedral molecule
by Haselbach, David 08 Dec '16

08 Dec '16

Hi everyone, sorry to ask such a basic question. I have a cryo EM density map 3.2 A of a icosahedral molecule and I already build the model of the monomer. I would like to place the remaining 59 copies and calculate the BioMT matrix for it. I started playing around with the sym command, but I couldn't get it working nicely. It's probably a problem of the coordinate system, but I couldn't figure it out. Than I thought there must be an automatic way and I tried Multifit but also this failed me miserably as the runs fail continuously with "stderr". So I was wondering is there a protocol to do this? Already thank you for any suggestions, David Dr. David Haselbach Max-Planck-Institute for biophysical Chemistry Department for structural Dynamics Am Fassberg 11 37077 Germany Tel. +495512011302

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Chimera-users December 2016