- Chimera-users - RBVI Mailing Lists

on MD movie and morph conformation by chimera
by Smith Liu 12 Jun '15

12 Jun '15

Dear All, Will you please introduce to me on how to combine chimera MD movie function and morph conformation function to make conformation change movie files to insert into PPT files? Smith

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mol2 for NH3
by MPI 11 Jun '15

11 Jun '15

Dear Users, I try to prepare a mol2 from pdb for ammonia (NH3) and ammonium (NH4+), respectively. I used two commands: addh and addcharge with am1 method. eg, addh addcharge all method am1 It turns out that Chimera gave two similar mol2 files for NH4+ but NOT for NH3. I wonder what command and parameters are needed to produce a correct mol2 for NH3. Here are the input pdb files for NH3 and NH4, respectively. # NH3 HETATM 2860 N NH3 A 402 53.512 -12.964 -36.364 0.88 45.66 N # NH4 HETATM 2858 N NH4 A 404 56.362 -12.467 -27.097 1.00 30.80 N Thanks, Dewey

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Problems detecting a left-handed helix
by Felipe Vasquez 11 Jun '15

11 Jun '15

Hi, I am trying to visualize several of the secondary structure details on a protein of interest, and I recently had notice (by several research papers) about the existence of a left-handed helix on it. However, I could not detect the helix using UCSF Chimera (it is simply considered as a loop). Why could this happen and how could be resolved? I have tried to modify the ksdssp cut-off parameter, but it was unsuccessful, so I think now that maybe the specific nature of the helix (left-handed polyproline-like type II) could be a bit tricky for the program. What would you suggest? Thanks in advance for your help an patience. Best regards, *Andrés Felipe Vásquez J., BSc, MSc.* Grupo de Fisiología Molecular Subdirección de Investigación Científica y Tecnológica Dirección de Investigación en Salud Pública Instituto Nacional de Salud Avenida calle 26 No. 51-20 - Zona 6 CAN +57 (1) 2207700 ext. 1419 Bogotá, D.C., Colombia

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Determination of angles formed by distances and ring axes
by Felipe Vasquez 10 Jun '15

10 Jun '15

Hi, I have problems trying to calculate the angle between two lines: one is really built as the distance between a residue atom from a protein and the centroid of a benzene ring (from a ligand), and the other is the line corresponding to the axis of the benzene ring. How could I accomplish this objective? I have read similar issues by chimera-users on the web, but I could not find enough information to complete the calculation (I could only estimate the first distance). In case of problems to clearly comprehend this particular task, please refer to the page 3, Fig 1, panel C in the attached research paper (phi angle). PD: Is it normal that the centroid of a benzene ring is above the ring itself? Because in the process of build the first distance, I don't know whether I have to calculate the distance between the centroid and the residue atom (which I found to be shorter), or instead calculate the distance between the center itself of the plane and the residue atom (which would be a bit longer). Thanks in advance for your time and assistance in this matter. Best regards, *Andrés Felipe Vásquez J., BSc, MSc.* Grupo de Fisiología Molecular Subdirección de Investigación Científica y Tecnológica Dirección de Investigación en Salud Pública Instituto Nacional de Salud Avenida calle 26 No. 51-20 - Zona 6 CAN +57 (1) 2207700 ext. 1419 Bogotá, D.C., Colombia

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file size of a trajectory
by MPI 10 Jun '15

10 Jun '15

Dear Users, I use the lastest version of Chimera to read trajectory (.xtc) files output from Gromacs ver 4.6.5. When a .xtc file size larger than 2GB in most cases and 1GB in some cases, Chimera gets choked and crashed. When a .xtc file size < 1GB, Chimera works very well. I wonder if this is a limitation for reading Gromacs trajectory files. Is there a solution ? Thank you. Dewey

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tetrahedral symmetry
by Morris, Kyle 10 Jun '15

10 Jun '15

Dear Chimera Developers, I have a volume reconstructed from Relion 1.3 imposing tetrahedral symmetry. Curiously, I am not able to find the symmetry group using: $ measure symmetry #0 Chimera returns C3, even with adjusting the parameters it uses to identify the symmetry group. The model is aligned as following the Xmipp convention for T symmetry (http://xmipp.cnb.csic.es/twiki/bin/view/Xmipp/Symmetry#T) which is the same as what Chimera calls T,z3? Any advice on getting the measure command to work in this convention would be greatly appreciated. Thanks! Best wishes, Kyle Morris University of Warwick, UK

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Save Cluster Figure as Phython Object
by Beuerle, Matthias 09 Jun '15

09 Jun '15

Dear all, I have been using the Clustering tool in the MD Movie/Analysis/Cluster to examine my trajectories and I found it very useful. Now I would somehow like to save the box-chart matplotlib object in order to adjust the figure, so that I can use it for a publication, since the dialog buttons do not allow a lot of modifications. Is this possible somehow? Alternatively I would be very happy as well if one could use the output obtained from the 'Save' button to recreate a similar figure (in which I have failed so far). Help is very much appreciated. Kind regards, Matthias

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joining two proteins
by López de Heredia Alonso, Miguel 08 Jun '15

08 Jun '15

Hi, I am new to Chimera, so perhaps someone could give me a hand. I have used Robetta for predicting the structure of a protein I am interested in and it gave back models for different parts of the protein. I would like to join them, so I am trying to join two models by a C-N peptide bond. I have selected the corresponding atoms in the last amino acid in one of the proteins and in the first amino acid of the other protein I want to join. With both atoms selected I took the "Join Models" option in "Build Structure" with the "C-N peptide bond" selected. And the "Apply" button does not activate. (See the screen shot attached) I have gone through the manual and I do not see what I am missing or what I am doing wrong. Any help is welcome. Thank you very much in advance. Kind regards, Miguel

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APBS electrostatic potential
by Felipe Vasquez 06 Jun '15

06 Jun '15

Hi, I am interested on calculating the electrostatic potential of a molecular surface on a protein (specifically visualizing that potential on a previously cavity determined by CASTp). However, althought I did get reasonable results using Coulombic potential, I could not obtain similar results using APBS potential (I obtained a surface too electrostatic, charged negatively and the values have a huge range, not only from -10 to 10 as in the case of Coulombic potential). Should I modify some default values out of the calculation parameters in order to get a similar result to that obtain by Coulombic potential? And it is absolutely indispensable add hydrogens in an APBS estimation? Thanks in advance for your help. Best regards, *Andrés Felipe Vásquez J., BSc, MSc.* Grupo de Fisiología Molecular Subdirección de Investigación Científica y Tecnológica Dirección de Investigación en Salud Pública Instituto Nacional de Salud Avenida calle 26 No. 51-20 - Zona 6 CAN +57 (1) 2207700 ext. 1419 Bogotá, D.C., Colombia

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surfaces and
by A G Szabo 03 Jun '15

03 Jun '15

I have been working with a very large structure of many subunits, the E.Coli Ribosome particle with the Signal Recognition Particle attached (PDB 2J28) I was able to create an image of the SRP part of the complex. I selected that subunit. And was able to hide all the other subunits. So with the subunit selected I tried to visualize only that image as a surface. Wouldn't let me, getting an error message that it was too large and I should somehow split it. Don't know how to do that. I know the whole dataset is very large, but the SRP portion is only 400 amino acids. A work around would be if I could somehow select the SRP subunit and have it as a dataset to reload as that subunit alone. Then not so big. Don't know how to do that either. Your suggestions. I couldn't find anything in the tutorials that might help. I was able to show the surface of another PDB file that was much smaller. Arthur G. Szabo Professor Emeritus Chemistry Wilfrid Laurier University Waterloo Ontario Canada.

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