May 2011 - Chimera-users - RBVI Mailing Lists

color side chain only
by Zhou, Ming (NIH/NCI) [C] 11 May '11

11 May '11

Hello, this is Ming Zhou at NCI-Frederick, Maryland. I am trying to use Chimera to make some ribbon structure figures. I am wondering how I can display only side chain (without backbone) for a specific residue. Usually, if I display the residue, select the residue at the Atom specifier and color it. The color would be partially on the ribbon structure too since the backbone of that residue is on the ribbon. How do I avoid coloring backbone, only color the side chain? Thank you very much. Ming

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Morphing volumes
by Burgoyne, Thomas 10 May '11

10 May '11

Hi, I have two 3D-EM volumes that I wish to use the morph option for. I can align the two maps in chimera by hand so that they sit well together but the problem is I want to be able to create a morph video from the maps new positions. When I use the morph option it only allows me to create a morph from the original set starting positions of each volume. Is there a way to get around this? I would be very thankful for any help or guidance. Tom

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Re: [Chimera-users] building large size polymer
by 윤홍민 05 May '11

05 May '11

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Re: [Chimera-users] imgCIF files
by Tom Goddard 04 May '11

04 May '11

HI Mattia, Chimera can save MRC2000 format which is nearly identical to CCP4 format. Any software that reads CCP4 will likely read the MRC output from Chimera as CCP4, but the origin of the map is specified differently. The MRC format allows a floating point origin specification which is not part of the CCP4 format and Chimera uses that. So alignment of the Chimera written MRC and atomic models may not work right in other software. A basic problem with CCP4 is that the origin has to lie on a crystallographic lattice point, which isn't so good for electron microscopy or maps from non-crystal sources. Chimera doesn't know about a SAXS bead radius in PDB header remarks. Also Chimera may try some heuristics to connect up the beads as if they were actual atoms. You'll have to try and see. You can adjust the sphere radius for the beads by selecting them and using Selection Inspector (green button in lower right of main Chimera window) or a command setattr a radius 5 #0 For making a simulated map with the Chimera "molmap" command the atom radius is not used. It simply adds 3-dimensional Gaussians centered at each atom. The Gaussian width is calculated by the resolution value used in the molmap command molmap #0 8 See the documentation for details. http://www.cgl.ucsf.edu/chimera/current/docs/UsersGuide/midas/molmap.html Tom > > Dear Elaine, > > thanks for your very fast and informative answer! I missed that option > in the list of Chimera commands. I will try it out tomorrow (I'm at > home now...). Perhaps it would be nice to add it to one of the > pull-down menus (in the Volume options?). Is there a way then to save > the map, say in ccp4 format? > > As for the SAXS file, yes, for instance the DAMMIN/DAMMIF-generated > files are in PDB format. But will Chimera read in the correct radius > for the beads, which is stored in the file header? (or is there a way > to externally enter the radius?). > > Thanks again - Mattia > > At 09.32 04/05/2011 -0700, Elaine Meng wrote: >> Dear Mattia, >> You can make a density map from atomic structures (or their parts) in >> Chimera using the "molmap" command: >> >> <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/molmap.html> >> >> For example, commands: >> >> open 2gbp >> molmap ligand 4.5 >> molmap protein 5 >> >> ... would make a map of resolution 4.5 for the ligand part of the >> structure (glucose) and another map of resolution 5 for the protein >> part of the structure. You could also specify the whole structure, >> particular chains, etc. >> >> If the SAXS model was in the form of a PDB file with the beads as >> "atoms," perhaps you could use a similar procedure. >> >> I hope this helps, >> Elaine >> ----- >> Elaine C. Meng, Ph.D. >> UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab >> Department of Pharmaceutical Chemistry >> University of California, San Francisco >> >> On May 4, 2011, at 7:44 AM, Mattia Rocco wrote: >> > >> > To the developers of Chimera: is there any intention of implementing >> the uploading of imgCIF density maps files? Such files can be >> generated by RasMol starting from either atomic structures or >> low-resolution bead models (e.g. SAXS-derived models). >> > >> > Conversely, it would be nice if density maps could be generated >> within Chimera... >> > >> > Best - Mattia >> > >

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solvent exposed charged resides
by George Feldman 04 May '11

04 May '11

Hello Chimera community, I am rather new to Chimera, but in general familiar with PyMol. I switched to Chimera for the added functionality and general "free-ness," and so far I like it, but I'm having difficulty getting started. What I really need to do is identify the solvent exposed (SAS) residues that are charged. In particular I would like to identify exposed lysines, arginines, glutamic acids, and aspartic acids. All I need to do is identify and count them, is there a way to do this without slowly going over the entire molecular surface? Please bear in mind that I am capable of typing in commands, but I am no programmer. If it is too complex, I will simply, and sadly, have to do it manually. My fear with the manual approach is that I will miss something or miss-classify it. Your advise and help is greatly appreciated. PS. I've tried to do Render by Attribute -> areaSAS, but that doesn't seem to be working for me even after I tell it to calculate the surface. I'm not sure what I'm doing wrong if this is the approach that I am supposed to be taking. Best regards, George

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imgCIF files
by Mattia Rocco 04 May '11

04 May '11

To the developers of Chimera: is there any intention of implementing the uploading of imgCIF density maps files? Such files can be generated by RasMol starting from either atomic structures or low-resolution bead models (e.g. SAXS-derived models). Conversely, it would be nice if density maps could be generated within Chimera... Best - Mattia Dr. Mattia Rocco Biopolimeri e Proteomica Istituto Nazionale per la Ricerca sul Cancro (IST) c/o Centro per le Biotecnologie Avanzate (CBA) IST c/o CBA, Largo Rosanna Benzi 10 I-16132 Genova, Italy Phone: +39-0105737-310 Fax: +39-0105737-325 e-mail: mattia.rocco(a)istge.it ATTENZIONE. Il presente messaggio ed i suoi allegati devono intendersi ad uso esclusivo dei suoi destinatari e sono confidenziali. Persone diverse dal destinatario, anche ai sensi del D.Lgs. n. 196/2003 , non debbono prendere visione dei contenuti, copiare od inoltrare l'e-mail a terzi. Se ricevete questo messaggio per errore, Vi preghiamo di cancellarlo, di distruggerne ogni copia e di informarci immediatamente. La mail non è un protocollo sicuro, pertanto IST declina ogni responsabilità in caso di intercettazione o modifiche del presente messaggio. WARNING. This message and any attachments is intended solely for the use of the intended addressees and is confidential. Any unauthorized review, use, disclosure or distribution is prohibited. If you receive this message in error, please delete it, destroy all copies and immediately notify us. Mail is not a secure protocol, therefore IST will not be liable for interception or amendment of this message.

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pause during morph conformations
by Charles Greenberg 04 May '11

04 May '11

I have a 3-state structure and I'm currently using morph conformations to interpolate between them. This works very nicely, but I'd like the output movie to pause for half a second (a few frames) during each of the three key states. Anyone know how to do this? I know you can add behaviors during particular frames, but I don't know how to make it pause. Thanks! --Charles

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Using Chimera to look at confocal data
by Thomas Burgoyne 04 May '11

04 May '11

Hi, I've been using Chimera for a few years now to look at electron tomography data and I have to say I think the software is absolutely superb. Recently I have started looking at 3D-confocal data and I discovered with a bit of work I can open the data using chimera. I open each colour channel as a separate image stack which works quite nicely. The only problem I encounter is when viewing the data using solid rendering only one channel is visible. Is there a way to view three image stacks at the same time using the solid rendering? Thanks, Tom

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partial failure in addH BUG?
by Francesco Pietra 04 May '11

04 May '11

Hello: i had partial failure in addH to a natural product. H at a quaternary, chiral C was not added in spite of repeated attempts. All Hs were added by my favorite drawer (for organic compounds); however, this changes the coordinates, which is not what I want. I solved the issue by transferring the chimera pdb output to vmd, adding the missing H with Molefacture. On the other hand, Molefacture, if asked to add all Hs, resulted in incorrect stereochemistry at -O-CH3 and some -C-CH3 (inverted umbrella, which could not be reversed). francesco pietra

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building large size polymer
by 윤홍민 02 May '11

02 May '11

2 1

Chimera-users May 2011