- Chimera-users - RBVI Mailing Lists

translation and rotation in MATLAB using transformation matrices from chimera
by Oleksiy Kovtun 10 May '17

10 May '17

Dear all, I need to merge two maps in MATLAB using alignment data from chimera. Inputs: two maps of the same box size, origin. I use matrixget - to report translation and rotation matrices for the aligned map . Translation operation works well when transferred into MATLAB (briefly, translation matrix gets converted in eulers and pased on to tom_rotate command in MATLAB, TOM package). However the x y z translation coordinates (the fourth column top to bottom in matrixget - output) are way off the real translation when using tom_shift command in MATLAB, TOM. I found out that if I open the rotated map and fit it again, it gives close to correct translation matrix. What's going wrong here? Does anyone have a solution how to overlay 3D arrays in MATLAB using chimera-reported transformation matrices? Many thanks, Oleksiy Dr Oleksiy Kovtun Research Fellow Briggs group MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK Tel: + 44 1223 267551 Email: okovtun(a)mrc-lmb.cam.ac.uk Dr Oleksiy Kovtun Research Fellow Briggs group MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK Tel: + 44 1223 267551 Email: okovtun(a)mrc-lmb.cam.ac.uk

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Multiple fitting of structures in to EM densities
by Healey, Joe 10 May '17

10 May '17

Dear chimera team, I have a large EM density I would like to fully populate with a number of copies of a protein. To be more specific, the EM density is of 2 concentric protein rings (EMDB-6720), and each concentric ring is stacked 3 or 4 times. Each ring is a hexamer, so I would like to populate every single ring with 6 copies of each protein (but the inner and outer rings are 2 different proteins). What would be the best mechanism to iteratively import a protein, populate an EM density space, then move on to the next one? Currently, I think if I was to simply open several copies of the protein, they would probably all try to fit within the same EM density position, leaving the rest of the structure empty? My apologies if this isn't totally clear, I've tried to explain it as best as I think I can. I'm happy to accept solutions in 'chimera language', python (or I also have Jaime's Pychimera installed). Many thanks Joe Healey M.Sc. B.Sc. (Hons) MSRB PhD Student MOAC CDT, Senate House University of Warwick Coventry CV47AL Mob: +44 (0) 7536 042620 | Email: J.R.J.Healey(a)warwick.ac.uk Jointly working in: Waterfield Lab<http://www2.warwick.ac.uk/fac/med/research/tsm/microinfect/staff/waterfield…> (WMS Microbiology and Infection Unit) and the Gibson Lab<http://www2.warwick.ac.uk/fac/sci/chemistry/research/gibson/gibsongroup/> (Warwick Chemistry) Twitter: @JRJHealey<https://twitter.com/JRJHealey> | Website: MOAC Page<http://www2.warwick.ac.uk/fac/sci/moac/people/students/2013/joseph_healey> | ORCID: orcid.org/0000-0002-9569-6738

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Re: [Chimera-users] Wire thickness
by Oliver Clarke 10 May '17

10 May '17

Hi Hernando, I used the ca_and_sidechains alias in this script (you should be able to get the individual commands from that). https://github.com/olibclarke/chimera-trimmings/blob/master/chimera_aliases… Cheers Oli > Dear Chimera > How do you set the thickness of the backbone and side chains independently to produce figures like the ones below (sorry I hijacked the picture used in blurred-display discussion). > > Thanks > > H.

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Wire thickness
by Hernando J Sosa 10 May '17

10 May '17

Dear Chimera How do you set the thickness of the backbone and side chains independently to produce figures like the ones below (sorry I hijacked the picture used in blurred-display discussion). Thanks H. [cid:image001.jpg@01D2C8F6.BEA06B60][cid:image002.jpg@01D2C8F6.BEA06B60]

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Re: [Chimera-users] Gaussian blur depth cueing? (ChimeraX)
by Tom Goddard 09 May '17

09 May '17

Before/after pair - at large size, I think the blur is helpful, but YMMV > On May 9, 2017, at 12:09 PM, Oliver Clarke <olibclarke(a)gmail.com <mailto:olibclarke@gmail.com>> wrote: > > Perhaps a better example: > > <brightness_blur.jpg> >> On May 8, 2017, at 10:07 PM, Tom Goddard <goddard(a)sonic.net <mailto:goddard@sonic.net>> wrote: >> >> Hi Oliver, >> >> The depth of field blur images I have seen of maps and molecules have all struck me as cool looking and less useful then conventional brightness based depth cuing. Brightness depth cue allows you to include more of the structure in back while reducing the obscuring effect it has on stuff in front. Blurring depth cue interferes much more with the stuff you want to be in focus. Your image minimizes the badness by not having any blurring in the central region of the image, but the periphery where there is blurring may be artistically nice, but I hope you are not looking at the structure there. >> >> That said the technique could be done using the depth buffer that assigns depth to each pixel — it can’t be done really well that way because that depth only gives the front-most object and if transparency is present the pixel shows multiple objects at different depths. I think it would require a compelling mock-up image to make it worth spending effort on this effect. It is relatively easy to make a mock-up image by using clip planes to save several images representing slabs at different depths, then blur each slab image differently depending on depth in a photo editor and composite. >> >> Tom >> >> >>> On May 5, 2017, at 6:42 AM, Oliver Clarke <olibclarke(a)gmail.com <mailto:olibclarke@gmail.com>> wrote: >>> >>> Hi, >>> >>> I was wondering if you have thought about implementing depth-dependent gaussian blur as a depth cueing mechanism in ChimeraX? >>> >>> The idea would be to blur the image in a manner dependent on the distance from the plane intersecting with the center of rotation, to mimick depth of field in a camera. >>> >>> Mocked up in the attached using a tilt/shift effect, but without access to real depth information - I wonder if it might better convey depth information than distance-dependent changes in brightness/contrast under some circumstances? >>> >>> Cheers >>> Oli >>> >>> <test_image_tilt_shift.png> >>> _______________________________________________ >>> Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu <mailto:Chimera-users@cgl.ucsf.edu> >>> Manage subscription: http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users <http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users> >> >

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Gaussian blur depth cueing? (ChimeraX)
by Oliver Clarke 09 May '17

09 May '17

Hi, I was wondering if you have thought about implementing depth-dependent gaussian blur as a depth cueing mechanism in ChimeraX? The idea would be to blur the image in a manner dependent on the distance from the plane intersecting with the center of rotation, to mimick depth of field in a camera. Mocked up in the attached using a tilt/shift effect, but without access to real depth information - I wonder if it might better convey depth information than distance-dependent changes in brightness/contrast under some circumstances? Cheers Oli

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Re: [Chimera-users] Query regarding chimera tool
by Elaine Meng 09 May '17

09 May '17

On May 8, 2017, at 10:54 PM, bushra TAJ <bushraistaj(a)gmail.com> wrote: > Hello Sir > I want to do some docking studies of my own synthesized compounds. I found them very active in some anti-cancer assays. > I will use AUTODOCK for this purpose. I have got the Pdb file of my target protein from PDB database. > My problem is how to make pdb of my molecule (input file for autodock) can I use chimera for that?? > I have chem-draw file format of my molecules will that open in chimera to make their pdb format. > Regards > In the menu under Tools….. Surface/Binding Analysis: There is a “Dock Prep” tool for preparing PDB files. There is also an “Autodock Vina” tool that will make prepared files in pdbqt format, but it will also run Autodock Vina docking (in other words, the prepared pdbqt files are a by-product but you could also use them as input to something else). You should look at the manual pages for more information. <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/dockprep/dockprep…> <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/vina/vina.html> Also in the future please send Chimera questions to chimera-users(a)cgl.ucsf.edu and include a useful subject line like “preparing molecules for docking.” Messages to my individual email address may not get answered. 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

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All-by-all distances
by Elaine Meng 09 May '17

09 May '17

> From: Elaine Meng <meng(a)cgl.ucsf.edu> > Subject: Re: Chimera Question > Date: May 8, 2017 at 6:03:55 PM PDT > > Hi Shawn, > I’m out sick… please send Chimera questions to chimera-users(a)cgl.ucsf.edu list. On second thought, I think I can answer quickly. However, for future reference please use the user list for Chimera questions and include a informative “subject” line to make it easier for others to find … thanks! Command: findclash :lys@n test self overlap -99999 log true … will put all the Lys N -> Lys N distances (within about 1000 A … just use a larger-magnitude negative overlap if you think there are longer distances) in the Log. It won’t be a table, though, just a list of distances that you would have to process yourself. Or instead of “log true” (or in addition to it) you could use the “saveFile” option to specify putting the same output into a text file. Command and options described here: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/findclash.html <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/findclash.html>> Output is like the following example for PDB 2gbp, with distances in the last column: 464 contacts atom1 atom2 overlap distance LYS 191.A N LYS 189.A N -1.010 4.290 LYS 223.A N LYS 227.A N -1.505 4.785 LYS 246.A N LYS 300.A N -3.378 6.658 […etc…] However I suspect maybe you meant NZ (the end of the sidechain) instead of the backbone N, in which case the command would be something like findclash :lys@nz test self overlap -99999 log true … with output like: 465 contacts atom1 atom2 overlap distance LYS 270.A NZ LYS 276.A NZ -1.932 5.212 LYS 308.A NZ LYS 246.A NZ -2.262 5.542 […etc…] Best, 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 8, 2017, at 4:14 PM, Shawn Sternisha <ssternisha(a)chem.fsu.edu> wrote: >> >> Hello Dr. Meng, >> >> Sorry to bother you but I have a question about Chimera that I have not been able to find an answer to, despite intensive web searches. I have seen your name on a lot of useful posts and answers so I figured I would give emailing you a shot. I have been searching for a method to measure all possible distance between Lys residues in a protein in a high-throughput manner. >> >> For example, if my protein has 17 Lys residues, is it possible to generate a table that has distance measurements between the N atoms of all of them. I believe that would be 231 possible distances. Any advice you could provide would be greatly appreciated. Thank you for your time in advance. >> >> Best, >> Shawn Sternisha >> PhD Candidate, Miller Laboratory >> Dept. of Chemistry and Biochemistry >> Florida State University > >

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calculate FSC curve between experimental cryo EM map and model
by #AHMED TOFAYEL# 08 May '17

08 May '17

Dear all, If I want to calculate FSC curve between experimental cryo EM map and model, what is the correct procedure to do so? I will explain what I have tried so far. Although I have variable local resolution in my map, according to FSC=0.143 criterion I have a 4 Ang map (say 1.mrc), I have used 'molmap' command in Chimera to generate a simulated map at 4 Ang. Then I used "vop resample" to take care of the pixel and box values ( then saved as 2.mrc). Thereafter, I have used "e2proc3d.py 1.mrc fsc.txt --calcfsc=2.mrc and plotted the fsc.txt file to get the curve. I am not sure if I am on the right track. My pixel size is 1.28. Best regards, Tofayel

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MD file naming
by P. Buscemi Ph.D. 08 May '17

08 May '17

Please,,,, How does one specify the output file name and location for molecular dynamics output ? regards Paul Buscemi, Ph.D.

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