April 2017 - Chimera-users - RBVI Mailing Lists

(no subject)
by Kavya Shankar 05 Apr '17

05 Apr '17

Hi, I would like to know how the axis of symmetry is calculated in a dimer as in the precise algorithm that is used to do this. Thank you. Regards, Kavya Shankar

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Defining glycosidic bond of nucleotide objects
by Charles-Alexandre Mattelaer 04 Apr '17

04 Apr '17

Dear Chimera-users I'm currently doing modeling on hexitol nucleic acids and using Chimera to visualize the trajectories. Since the atoms in the hexitol-ring are numbered differently than in the standard ribose, Chimera has some difficulties displaying the correct ribbon (backbone) and slab (bases). I've been able to define my own ribbon style using the Ribbon Style Editor and creating a new ribbon style based on the standard 'nuleic acid' trace and replacing the existing backbone atoms with the corresponding atom names for the non-standard hexitol residues. The main problem is setting a slab object to replace the base atoms. The 'nucleotide objects' settings are based on a glycosidic bond on the C1' of ribose. In HNA the glycosidic bonds are found on C2' of hexitol. I believe this is causing the problem. Additionally, I can add that using the 'ladder'-like objects, a gap between the 'steps' and the backbone occurs. (I've tried setting the base as anchor but to no avail.) I was wondering if there would be a way to redefine the anchor atom of the nucleotide objects? (I searched in the manual but haven't found any ways to redefine the anchor itself.) This would greatly improve visibility of larger oligonucleotides and would help me a lot. Kind regards and thank you in advance Charles-Alexandre Mattelaer

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attributes
by John Mercer, Ph.D. 04 Apr '17

04 Apr '17

Hi, If you have a structure file so large that it needs loaded as two separate files, e. g. a ribosome, is it still the case that a designer attribute file for individual subunits across the whole structure would still be handled by the usual single file attribute mechanism or is something else necessary? Does ChimeraX have an attribute mechanism that is the same as Chimera? Best, -John Mercer Duke University

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another question
by Arthur Szabo 04 Apr '17

04 Apr '17

In the menu used to save images there are two boxes, one for the image width and the other for the image height In the part of the menu below I have set the pixel units for the image width to 5000, with the height being automatically set. These are not the default settings. How can I make them the default settings? In the version of Chimera that I recently downloaded the default settings were 1600 and 796, respectively. The default settings of the former chimera download (my computer had been corrupted so downloaded Chimera again). I can't find anywhere in this image saving menu to change the default settings. Thank you Arthur G. Szabo [cid:image001.png@01D2AD56.F614B2B0]

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[summovie]
by Edoardo D'Imprima 04 Apr '17

04 Apr '17

Hi Oli, one quick question: I noticed the interesting question you posted on the Unblur forum regarding the use of summovie. Did actually worked out the “corrected” version by Tim that should allow you to perform dose weighting and saving the aligned movies? Cheers, Edoardo --------------------------------------------------- Edoardo D'Imprima PhD Student Max Planck Institute of Biophysics Structural Biology Department Max-von-Laue Straße 3 60438 Frankfurt am Main Germany Tel: +49 (0) 69 6303 3015

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(no subject)
by Kavya Shankar 03 Apr '17

03 Apr '17

Hi, I learnt that a dimer axis of symmetry is got by using matchmaker and then the rotation is measured from it. I would like to know the algorithm that is used to calculate the axis of symmetry and how exactly it is done if possible. Thank you. Regards, Kavya Shankar

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active questions
by Arthur Szabo 03 Apr '17

03 Apr '17

I am working with a structure that is largely a protein, and there is a short oligonucleotide associated with it. In the tools menu the sequence of the protein is Chain A and the short oligonucleotide is Chain C. I have shown their respective sequences. I also know how to highlight components of each chain etc. However, there is a short dinucleotide with two thymine residues that are also part of the structure. I was able to select these residues and the two thymine residues in the oligonucleotide by using the SELECT menu: residues: dT. So in total four thymine residues are selected and with the ACTIONS menu I can visualize them. Going to Chain C I can hide the two thymine residues on the longer oligo. How can I select the other two thymine residues that make up the short dinucleotide? One of these thymines is covalently bound to a tyrosine residue through a phosphodiester bond. I can visualize the tyrosine monophosphate through Chain A, and one can see it connected to the relevant thymine residue. But I would like to color the two thymine residues. But I cannot select them or at least I do not know how to select them. I am not an expert at using the command line. Likely there is something there. Again your assistance is sincerely appreciated. Arthur G. Szabo

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Stereo
by Arthur Szabo 03 Apr '17

03 Apr '17

Is it possible to create a stereo view image from a single pdf image. I have colored different segments of the original pdf image. Thanks A G Szabo agszabo(a)outlook.com<mailto:agszabo@outlook.com>

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Residue information failed
by Kunrong Mei 03 Apr '17

03 Apr '17

Hi all, I have met a problem as I used the mouse pointer to show the residue information. Normally, Chimera automatically displays the residue information (residue name, model ID, chain ID, and residue number...) by default when the mouse pointer is placed at a special position. This is ultra helpful when analyzing structures. My problem is that, after I registered to Chimera today, this function lost and it doesn't show the residue information any more. Has anyone met this kind of problem before? Or does anyone know how to fix it? Thanks, Kunrong

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Re: [Chimera-users] Chimera comparing homodimer with flipped homodimer
by Elaine Meng 03 Apr '17

03 Apr '17

Hi Kavya, The “mm” command used to align the structures and “measure rotation” used to report the resulting rotation are fully described in the documentation, see <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/mmaker.html> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#rotation> Regards, Elaine > On Apr 3, 2017, at 8:15 AM, Kavya Shankar <kavshank(a)umail.iu.edu> wrote: > > Hi Elaine, > > I want to know exactly how the axis of symmetry has been calculated for the dimer. What coordinates are used to perform the alignment of the chains? This will really help me out with my research. > > Thank you. > > Regards, > Kavya Shankar > > On Thu, Mar 30, 2017 at 11:25 AM, Elaine Meng <meng(a)cgl.ucsf.edu> wrote: > Hi Kavya, > I didn’t have a good example handy yesterday, but here is a more specific example, in commands: > > open 5hvp > open 5hvp > mm #0:.a:.b #1:.b:.a pair ss > show :241.b > measure rotation #0 #1 > > This opens PDB 5HVP twice, matches it to itself except pairing A in one with B in the other and vice versa, shows only residue 241 in chain B so that you can see pairing is A-B, and measures axis of rotation between the two copies of 5HVP. The measurement is also reported in the Reply Log (open from Favorites menu): > > Position of 5hvp (#1) relative to 5hvp (#0) coordinates: > Matrix rotation and translation > -0.32555997 0.82635225 -0.45951350 0.78339640 > 0.82635225 0.01248149 -0.56301524 15.06413576 > -0.45951350 -0.56301524 -0.68692152 28.23994571 > Axis 0.58070648 0.71150597 -0.39565040 > Axis point -5.75571422 -0.00000000 18.30836454 > Rotation angle (degrees) 180.00000000 > Shift along axis 0.00000000 > > I also attach an image below. > 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 > > <flip-axis.png> > >> On Mar 29, 2017, at 10:10 AM, Elaine Meng <meng(a)cgl.ucsf.edu> wrote: >> >> Hi Kavya, >> I think I understood you, but I can only repeat the same answer. I do not know of any way to get the axis in Chimera except by first superimposing two copies of the dimer. Open the AB dimer twice (A1-B1 and A2-B2), superimpose A1 to B2 and B1 to A2. Then if you still care about where the axis is you can calculate it from the already superimposed structures with “measure rotation.” >> Elaine >> >>> On Mar 29, 2017, at 10:05 AM, Kavya Shankar <kavshank(a)umail.iu.edu> wrote: >>> >>> Hi, >>> >>> To be more specific, I want to find the two-fold symmetry axis in the dimer so that when I rotate the original structure I get another structure that is similar to the first with the chains' positions interchanged. >>> >>> Thank you. >>> >>> Regards, >>> Kavya Shankar >>> >>> On Wed, Mar 29, 2017 at 12:18 PM, Elaine Meng <meng(a)cgl.ucsf.edu> wrote: >>> >>>> On Mar 29, 2017, at 9:01 AM, Kavya Shankar <kavshank(a)umail.iu.edu> wrote: >>>> >>>> Hi, >>>> Is it possible to find the axis of symmetry for a dimer? I am looking to rotate the dimer along this axis by 180 degrees so that I can compare the two structures. >>>> Thank you. >>>> Regards, >>>> Kavya Shankar >>> >>> Hi Kavya, >>> Why not just match (superimpose) one monomer to the other and compare directly? At least from the Chimera perspective, the question seems backwards because maybe you could figure out the axis AFTER matching. However, if the purpose of finding the axis is just to compare the monomers, I would just superimpose them and forget about the axis. If you had dimer A-B you could either “split” (command) and match A to B, or you could open A-B twice and match A1 to B2 (and/or B1 to A2). This page discusses the ways to superimpose structures in Chimera; probably Matchmaker (GUI or command) would be the easiest. >>> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/superposition.html> >>> >>> After two models are superimposed, you can get the axis and rotation amount with command “measure rotation” >>> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#rotation> >>> >>> 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 >>> >>> P.S. seemed like a user question so I put it on the chimera-users list … chimera-dev is more for programming issues >>> >>> >>> _______________________________________________ >>> Chimera-dev mailing list >>> Chimera-dev(a)cgl.ucsf.edu >>> http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-dev >> > >

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