August 2006 - Chimera-users - RBVI Mailing Lists

question about annealing residues in pdb file
by Shah, Sanket S 01 Sep '06

01 Sep '06

Hello, I have been using chimera extensively for pdb rendering and manipulation. I needed some information that i couldn't find in the archives. I am aware that chimera displays the pdb file according to the co-ordinates mentioned in the pdb file. However in my situation I have changed co-ordinates of some of the secondary structure elements like helices to do a better fit. and I have saved the new coordinates in the same pdb file. So now when i render this pdb file it shows me the structure with the modified orientation, however chimera displays a continuous model. In the sense, the breaks that I had introduced by changing the angles of some of the helices and thus making the linkage discontinuous are somehow annealed by chimera. So my question is what sort of algorithm chimera employs to seal breaks in the pdb structure. The same pdb strucutre when viewed in swiss model deepview software contains gaps/breaks at the junctions where the coordinates of the helices have been modified from the original ones. however no such breaks are seen when displayed through chimera. First I thought chimera does energy minimization to find out the best way to arrange the loops between the helices so as to create the best continuous structure. However it seems that chimera doesn't do energy minimization, yet it's able to display a complete structure. Could you please inform me about how this is accomplished. Thanks Sanket

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change chain id
by Yunierkis Perez Castillo 29 Aug '06

29 Aug '06

Hi all, I need to change the chain ID for a protein, that is, change the chain A to chain B. Can I do that with chimera? Thanks in advance Yunierkis

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addH/removeH for charged a.a.
by Dave Roe 26 Aug '06

26 Aug '06

Is there functionality that will - add a hydrogen (if needed) to all Lysines and Arginines to give the protonated form - remove a hydrogen (if needed) from Aspartic and Glutamic acids to give the deprotonated form? -- Dave Roe roex0050(a)umn.edu

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Volume color zones
by hsosa＠aecom.yu.edu 21 Aug '06

21 Aug '06

Is is possible to use different colors for different Volume zones ?. I have a volume (MRC format) and have defined two marker sets using the Volume-Path-Tracer. Then I select one of the path and colored the surface volume around using the Volume Color Zone utility. This work fine but then if I selected the other markers and do the same the volume close to the new markers get colored but anything else get uncolored, including the areas previously colored. Am I doing something wrong ?. Can I color several Volume zones independently ? Thanks Hernando --

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RealD (Stereographics) E2SGI emitter on Quadro 3450?
by Sabuj Pattanayek 19 Aug '06

19 Aug '06

Hi all, Anyone know if it's possible to use a RealD (Stereographics) E2SGI emitter on Quadro hardware? Thanks, Sabuj Pattanayek

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addH utility and PDB files
by Nihshanka Debroy 15 Aug '06

15 Aug '06

Hi, I have a couple of questions about the addH utility built into Chimera, and about PDB files in general. I used addH to protonate (add hydrogens) to PDB files. Does it use a force field of some kind in the process, like Amber or Charmm? It seems that depending on the force field used to protonate a PDB, the values for the partial charges and the van der waals radii are different. Specifically, I am using these charges and radii in the DelphiController. Another thing I've noticed is that when adding hydrogens, for the same amino acid, the hydrogens are sometimes different in name or number. For example if I have a Cysteine, in some cases, an HG (gamma hydrogen) is added for the gamma sulphur, balancing out charges completely. In other cases, the HG is not added, and so the amino acid ends up with a net negative charge. I was just wondering if this is supposed to happen. Here's another example. For Alanine, I was getting 1H, 2H and 3H attached to the nitrogen in some cases. In other cases, I just got "H" attached to the nitrogen. Does this mean those particular instances of ALA in the PDB had one only hydrogen attached to the nitrogen, instead of 3 ? Wouldn't the missing 2 hydrogens lead to a net negative charge on the ALA? Thanks for all the help and for this mailing list. It is a wonderful resource. Sincerely, Nihshanka Debroy

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Surfactant
by Annalisa Mercuri 15 Aug '06

15 Aug '06

Hallo everybody, I'm working with surfactants and emulsions. I'd like to use Chimera to reconstruct a micelle with my components, but I have no clue how to do that. Further my emulsion is made by a mixture of two surfactants. I would like to have a emulsion droplet image like the virus one. What do you suggest? Thank you for your help and advices Annalisa Mercuri MSc PhD Student School of Chemical Sciences and Pharmacy University of East Anglia Norwich Norfolk NR4 7TJ UK

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structure slice
by Raquel Hernandez 15 Aug '06

15 Aug '06

Hello chimera e-mail, I have received from a colleague data set from a virus reconstruction. I am a novice in the use of your program but have managed to make an image of my virus. I would like to add an image of a slice of the virus through the center perpendicular to the three fold axis. Can you please advise me on what I need to do to make a slice? I can get the tech people here to help if you tell me the tools, etc that I need to use. Thanks. Raquel Raquel Hernandez Research Associate Professor Department of Molecular and Structural Biochemistry 128 Polk Hall North Carolina State University Raleigh, NC 27695 office:919-515-5765 lab: 919-515-5786 Fax: 919-515-2047

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Fwd: Chimera and Macs
by Elaine Meng 14 Aug '06

14 Aug '06

Hello Mac users! When the Chimera window gets obscured by other windows on a Mac, clicking the X11 icon will bring it to the front (assuming you are using the recommended Mac/X11 version of Chimera). Begin forwarded message: > From: Kevin Dalby <dalby(a)mail.utexas.edu> > Date: August 13, 2006 11:54:43 PM PDT > To: Elaine Meng <meng(a)cgl.ucsf.edu> > Subject: Re: Chimera and Macs > > Hi Elaine > > I think we spoke briefly at the enzymes GRC. > > I am not a sophisticated chimera user. I use it on my mac while > working with another 10 programs . Usually i cant see the chimera > screen when i need it. Normally, when I want to get back to a > program that is hidden i go to the doc and just click on the > program icon and it comes to the front. This does not happen for > chimera. I know other spoilt mac users would enjoy a remedy. > > > best wishes > > Kevin > > > Kevin Dalby > Associate Professor of Medicinal Chemistry > University of Texas at Austin > tel 512-4719267 > fax 512-2322606 > > > > ----- Elaine C. Meng, Ph.D. meng(a)cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html

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spaceball
by Mario Halic 09 Aug '06

09 Aug '06

hi!, can I use spaceball 5000 as input device in chimera? thanks, Mario

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