- Chimera-users - RBVI Mailing Lists

Re: [Chimera-users] mRNA Structure
by Elaine Meng 03 Dec '21

03 Dec '21

> On Dec 3, 2021, at 6:44 AM, SANDOVAL, KENNETH <K.SANDOVAL1(a)nuigalway.ie> wrote: > > Hello, > I have a predicted secondary structure of an mRNA molecule. I am interested in trying to visualize this with UCSF Chimera. But I'm unsure what file format the program accepts for this? Does it need some sort of mRNA equivalent of a .pdb file? > Thank you, > Kenneth Hello Kenneth, The recommended address for Chimera questions is chimera-users(a)cgl.ucsf.edu CC'd here. By secondary structure I'm guessing that you mean the base-pairing pattern, and not actually 3D atomic coordinates. For Chimera you would generally need 3D atomic coordinates, most commonly in PDB format. If that is really what you have (base-pairing information only), then here are two ideas for building a 3D structure in Chimera using that information: (1) The RNArtist plugin to Chimera - quite extensive, has a lot of nice features, needs to be downloaded separately: <https://github.com/fjossinet/RNArtist> <https://www.rbvi.ucsf.edu/chimera/plugins/plugins.html> (2) The "rna" command in Chimera can also build models but much more roughly. See "rna model": <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/rna.html> <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/rna.html#model> 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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Re: [Chimera-users] .dae export for ChimeraX
by Tom Goddard 02 Dec '21

02 Dec '21

Hi Byrne, I agree, OBJ and STL are very limited compared to Collada and GLTF. OBJ is supported by almost every 3D model program and STL is commonly used for 3D printing (single color) which is why they are in ChimeraX. GLTF is definitely the best option in ChimeraX for your case. There appear to be lots of programs that convert GLTF to Collada and the other direction too. But I have not tried any of them so don't have any recommendation. Let us know if you find one that works well -- other ChimeraX users may have the same need. A major stumbling block exporting 3D models from ChimeraX (or Chimera) is that they use vertex colors, while most of the non-biology 3D model world uses texture colors, and will simply ignore vertex colors losing all your color information. That example I linked to in the last email describes a relatively new ChimeraX feature to export texture colors (for limited cases, e.g. discrete colors only). Another common problem exporting molecular models for use in other software is that the file size and number of triangles is too large for the application that you want to use them in, often tens of millions of triangles or hundreds of Mbytes to Gbytes in size. The example also shows how to tell ChimeraX to limit the number of triangles. https://www.rbvi.ucsf.edu/chimerax/data/texture-may2021/export_3d.html Tom Model from gltf export from linked ChimeraX example > On Dec 2, 2021, at 2:04 PM, Byrne Pedit <bpedit(a)comcast.net> wrote: > > Hello Tom, > > Thanks for the response. I tried the GLTF export, not recognizable by Xcode (the development platform for iOS and Mac OS). The only ChimeraX file options I’ve found to be openable are OBJ and STL. These are, however, problematic and unusable. > > But your hint of using GLTF as an intermediary offers an avenue for exploration, it’s not a format I’ve used. I see it supports scene graph hierarchy, absent with OBJ and STL( exported from ChimeraX anyway) so this is promising. Now to find a converter. > > The GLTF export link is informative, it may help further refine my approach. Interestingly, the molecule you’ve chosen for demo purposes appears to be the one, or a variant thereof, I’ve been testing with! > > Thanks again, > > Byrne > > >> On Dec 2, 2021, at 12:30 PM, Tom Goddard <goddard(a)sonic.net <mailto:goddard@sonic.net>> wrote: >> >> Hi Byrne, >> >> We have long been interested in adding Collada format export of scenes from ChimeraX. Here is the feature request for that >> >> https://www.rbvi.ucsf.edu/trac/ChimeraX/ticket/485 <https://www.rbvi.ucsf.edu/trac/ChimeraX/ticket/485> >> >> But our scene export in ChimeraX has focused on GLTF format, as that has been the most requested. Here is an example showing GLTF export from ChimeraX (including texture colors). >> >> https://www.rbvi.ucsf.edu/chimerax/data/texture-may2021/export_3d.html <https://www.rbvi.ucsf.edu/chimerax/data/texture-may2021/export_3d.html> >> >> ChimeraX also exports OBJ, STL, X3D, VTK as shown in the save command docs >> >> https://rbvi.ucsf.edu/chimerax/docs/user/commands/save.html#formats <https://rbvi.ucsf.edu/chimerax/docs/user/commands/save.html#formats> >> >> Can you make use of GLTF files? If not, a quick solution might be to convert ChimeraX GLTF files to Collada with third-party software. >> >> Tom >> >>> On Dec 2, 2021, at 10:41 AM, Byrne Pedit via Chimera-users <chimera-users(a)cgl.ucsf.edu <mailto:chimera-users@cgl.ucsf.edu>> wrote: >>> >>> ChimeraX is awesome and definitely superior to the original but for the inability to export as .dae (Collada). Is that possibly on the to-do list? This is important for those of us (just me?) writing interactive molecular apps for devices. It is the only satisfactory path I’ve found between a PDB file and SCNNodes/Scenes in iOS. (See the iOS app ‘BioMole’, free, if interested in an application.) >>> _______________________________________________ >>> Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu <mailto:Chimera-users@cgl.ucsf.edu> >>> Manage subscription: https://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users <https://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users> >>> >> >

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UCSF software cannot be opened normally
by 免孑 02 Dec '21

02 Dec '21

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.dae export for ChimeraX
by Byrne Pedit 02 Dec '21

02 Dec '21

ChimeraX is awesome and definitely superior to the original but for the inability to export as .dae (Collada). Is that possibly on the to-do list? This is important for those of us (just me?) writing interactive molecular apps for devices. It is the only satisfactory path I’ve found between a PDB file and SCNNodes/Scenes in iOS. (See the iOS app ‘BioMole’, free, if interested in an application.)

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Curiosity regarding amino acid category in UCSF chimera
by Prathvi Singh 01 Dec '21

01 Dec '21

Hi, In UCSF chimera, when I go to Select > Residue > Amino Acid Category > Hydrophobic, the LYSINE residues also get selected. However, according to the Kyte-Dolittle scale, LYSINE is a fairly hydrophilic residue. Is there any specific reason why chimera lists them as hydrophobic residues? -- Prathvi Singh, Research Fellow, Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur-208016

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Minimization on complex
by Francesca Magarotto - francesca.magarotto2＠studio.unibo.it 29 Nov '21

29 Nov '21

Hi, I need an advice regarding minimization of complexes. I've performed a virtual screening and I've selected some molecules of interest. Now, I've looked for the possibile interactions in the binding site and I would like to perform a minimization moving only the hydrogen atoms in the binding site. However, I have to create a new file pdb complex formed by my protein and one molecule from VS results. So, I opened the pdb file of the protein and the mol2 file of the molecule from the VS: now, do I need to save a pdb file of the complex and how to save it? I need the hydrogens to move according to the ligand inside the protein and I don't know if it's possibile with both the type of saving (is it better individual MOLECULE sections or combined MOLECULE section?). Moreover, I don't know if (for this kind of purpose) it's better first to save the complex in pdb file and then to use dockprep and minimization or use dockprep and minimization and only after saving the file of the complex. My main aim is to see if some hydrogens of the residues in the binding site move their places according to the presence of this ligand. Hope someone can help me, thanks.

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Get Minimization Energy
by Leonard Zhao 26 Nov '21

26 Nov '21

Hello, I am running a Python script to perform multiple structure minimizations and I need to extract to final potential energy from each minimization. I see that the potential energy is usually reported in the Reply Log, but when IDLE is open, it is instead redirected to IDLE. Is there any way to redirect it back to the Reply Log so I can more easily extract it in my script, or is there some other method to easily extract the energy value programmatically? Thanks, Leonard Zhao

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question regarding UCSF Chimera FindHBond feature
by Aditi Laddha 25 Nov '21

25 Nov '21

Hello, I have been using the FindHBond feature of Chimera for finding hydrogen bonds between water molecules and the polypeptide chains. I need to use some specific distance and angle criteria to find H-bonds, so I wanted to ask what is the default distance (D....A) and angle criteria (D-H....A) used in the software to find out the H-bonds, -- Regards, Aditi Laddha PhD Scholar Indian Institute of Technology, Kanpur, Uttar Pradesh 208016

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how to rectify error No MMTK name for atom
by Smriti Singh 2018RBT01 24 Nov '21

24 Nov '21

hello administrator, I am trying to minimize the Nucleotide sequence (DNA aptamer) through chimera. While performing energy minimisation steps, Chimera error "No MMTK name for atom 'HO5' in standard residue 'DA' showed. Please let me know how to rectify this issue. With warm regards Smriti Singh Research Scholar Department of Biotechnology MNNIT Allahabad

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Color volume series by per voxel variance?
by Oliver Clarke 24 Nov '21

24 Nov '21

Hi all, Is there any way in either Chimera or X to calculate the per voxel variance of a volume series, and then use that to color the individual voxels in each frame? When one has a series of volumes showing a subtle conformational change - lets say identified using cryoDRGN or 3D variability analysis in cryoSPARC - it would be nice to be able to visually highlight on the map the region that is changing the most, in some kind of quantitatively sound way. Often local changes are visually apparent when looking at the maps and rotating them around, but don't necessarily stand out in a movie of the whole volume. Coloring the series of maps (which are all on the same grid) by the variance of the density value at each voxel might be one way to visualize this. Is this possible? Cheers Oli

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