April 2015 - Chimera-users - RBVI Mailing Lists

on script which can be read and executed by chimera
by Smith Liu 17 Apr '15

17 Apr '15

Dear All, Will you please introduce to me a web link on how to compile and edit scripts which can be read and executed by Chimera? I am looking forward to getting your reply. Smith

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the "select" funtion of mouse is disable
by sunyeping 16 Apr '15

16 Apr '15

Dear all,I find the "select" funtion of mouse in Chimera is disable. I can not use "ctrl+left mouse button" to select any item in the structure. Have you met this problem before? My systems is windows 7 and the Chimera version is 1.10.1. How to solve this problem? Do I need to change some setting?Best regards,Yeping Sun Institute of Microbiology, Chinese Academy of Sciences

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Re: [Chimera-users] Reducing the map to a cubic box
by Tom Goddard 15 Apr '15

15 Apr '15

In Chimera “atoms” means an atomic model, for example from a PDB file, not a density map. If you want to reduce your map to a cube by cropping and it is size 54,36,51 use command volume #0 region 0,0,0,35,35,35 That gets the lower left corner. To get the center part volume #0 region 9,0,7,44,35,42 The 6 numbers are imin,jmin,kmin,imax,jmax,kmax where i,j,k are indices along the 3 map axes. You can also do this with the Volume Viewer dialog menu entry Features / Region Bounds, or interactively with the mouse using Features / Subregion Selection. For more info about map manipulations http://www.cgl.ucsf.edu/chimera/data/tutorials/volumetour/volumetour.html Tom > On Apr 15, 2015, at 1:17 PM, Sushree Tripathy wrote: > > Hi, > > Thanks for your prompt reply. What I am trying to do is I have a map which I have loaded in chimera as #0. Now I want to reduce it to cubic size. Since the syntax is "vop boxes <> volume-spec atom-spec <https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/frameatom_spec.html> size d", so I am choosing #0 for my volume and all the atoms in that volume. so #0 again. Please correct me if I am wrong. > > > Thanks > Sushree. > > Sushree Tripathy > Graduate Student > Department of Physics > University at Buffalo > > On Wed, Apr 15, 2015 at 4:13 PM, Tom Goddard wrote: > Hi Sushree, > > Why does your "vop boxes” command use model #0 for both the map and the markers? That can’t be right. If your marker(s) are in model #1 you would need “vop boxes #0 #1 size 36”. What are you trying to do? > > http://www.cgl.ucsf.edu/chimera/current/docs/UsersGuide/midas/vop.html#boxes <http://www.cgl.ucsf.edu/chimera/current/docs/UsersGuide/midas/vop.html#boxes> > > Tom > > > >> On Apr 15, 2015, at 1:03 PM, Sushree Tripathy wrote: >> >> Hi, >> >> I went through the chimera user's guide and as per the syntax used "vop boxes #0 #0 useMarkerSize true" or "vop boxes #0 #0 size 36" (the simplest case) to create a cubic box from my density map (54, 36, 51). It is neither giving me any error nor giving me the output map. >> >> Please help. >> Thanks >> Sushree. >> >> >> Sushree Tripathy >> Graduate Student >> Department of Physics >> University at Buffalo >> _______________________________________________ >> Chimera-users mailing list >> Chimera-users(a)cgl.ucsf.edu <mailto:Chimera-users@cgl.ucsf.edu> >> http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users <http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users> > >

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Reducing the map to a cubic box
by Sushree Tripathy 15 Apr '15

15 Apr '15

Hi, I went through the chimera user's guide and as per the syntax used "vop boxes #0 #0 useMarkerSize true" or "vop boxes #0 #0 size 36" (the simplest case) to create a cubic box from my density map (54, 36, 51). It is neither giving me any error nor giving me the output map. Please help. Thanks Sushree. Sushree Tripathy Graduate Student Department of Physics University at Buffalo

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generating a map from a atomic model with the same size of its reference map
by 李智海 14 Apr '15

14 Apr '15

hi, here I want to generate a density map from a atomic model in Chimera, then convert the generating map into .pif file to do as the initial map performing in Auto3dem. I have met some questions to successfully finish these work. 1.How can I generate a mol-map from a fitting model with identical dimensions, center coordinates and pixel size of its reference map. I have tried to use “Fit in map”, but the generating map differed from its fitted map in the map size. 2. The mrc map created in Chimera has dimension of even number of columns. If I set the column number to odd number, is it ok (for example, if the origin is off by half pixel?). The reason I am asking such a question is that I will convert this mol-map to pif format, and pif format map has dimension of odd number columns. Thanks in advanced! Best wishes! Zhihai Li

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generating a map from a atomic model with the same size of its reference map
by 李智海 14 Apr '15

14 Apr '15

hi, here I want to generate a density map from a atomic model in Chimera, then convert the generating map into .pif file to do as the initial map performing in Auto3dem. I have met some questions to successfully finish these work. 1.How can I generate a mol-map from a fitting model with identical dimensions, center coordinates and pixel size of its reference map. I have tried to use “Fit in map”, but the generating map differed from its fitted map in the map size. 2. The mrc map created in Chimera has dimension of even number of columns. If I set the column number to odd number, is it ok (for example, if the origin is off by half pixel?). The reason I am asking such a question is that I will convert this mol-map to pif format, and pif format map has dimension of odd number columns. Thanks in advanced! Best wishes! Zhihai Li

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Fitting pdb model into difference map
by Chinaza Egbuta 13 Apr '15

13 Apr '15

I generated an Fo-Fc difference map using CCP4i and was able to superimpose the PDB model structure onto the map in Coot but I am unable to do so with Chimera. The model and map are offset/rotated away from each other and I have not been able to fit the model into the map with Volume Viewer --> Tools --> Fit in Map. Please let me know how I can get around this issue. Thank you. CE

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Extracting masked map region using selected sop piece?
by Oliver Clarke 13 Apr '15

13 Apr '15

Hi all, I find the sop command (particularly 'sop split' and 'sop hideDust metric volume rank') to be very useful for viewing a molecular envelope at a low threshold in an otherwise noisy map. I would like to save the volume enclosed by a single sop piece as a separate volume, but it does not seem like this is possible - when I select a sop piece and use 'volume nameregion’ to assign it a name, and then attempt to write just that region to an mrc, it saves the whole map. Is there some way to do this that I am missing? I realize that a similar outcome can be achieved with segger, but for larger maps this can be very slow (and potentially involve multiple cycles of selection and regrouping), whereas sop operations are almost instantaneous, so I feel it would be a valuable adjunct capability to that offered by segger. Also, the behaviour of sop split seems a little counterintuitive to me. When I use 'sop split' on a volume, it generates a new model with a different ID for the split map - fine so far. However, the original map seems to be completely invisible - it is listed as displayed in the model panel, but if I undisplay the split map in the model panel and toggle display of the original map in the model panel, nothing happens. If I go to the volume viewer, the original map is listed as displayed, and if I toggle it off and then on again there, it reappears. It seems like it would be maybe simpler for the user to just automatically undisplay the original map upon creation of the sop split map, but not to prevent the user from redisplaying it in the model panel. Here is a link to a screen recording demonstrating what I mean: https://www.dropbox.com/s/g40u9dhj0xslcbf/sop_split.mov?dl=0 <https://www.dropbox.com/s/g40u9dhj0xslcbf/sop_split.mov?dl=0> Best, Oliver.

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Fitmap on overlap/correlation only within bounds of smallest map
by Oliver Clarke 13 Apr '15

13 Apr '15

Hi, I am trying to fit a set of large (whole protein) maps to a map corresponding to a single domain of the protein (extracted using ‘vop zone minimalbounds true’ with an atomic model of the domain in question. It works fine, except that it takes rather a long time (~2000 steps), and the final correlation is 0.33, which is strange because the overall correlation between the two complete maps is ~0.95, and I can see that the final overlap between the aligned maps is good. It seems like ‘fitmap’ is calculating the correlation/overlap based on all grid points in the map that I am aligning, which has a much larger box size than the map to which I am aligning it. Is there any way to restrict the metric analysis to just consider points within the smaller box of the reference map? I cannot find such an option in the documentation for fitmap. The use case for this is when one has multiple conformations of a protein (for example, EM volumes after 3D-classsification) and would like to align them on a single reference domain. Best, Oliver.

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Ways to minimize data loss during resampling?
by Oliver Clarke 13 Apr '15

13 Apr '15

When one has multiple maps corresponding to the same protein in different conformations, it is convenient to save aligned copies of each map, for easy comparison later or for transfer to other programs. This requires interpolating the map to be aligned on the grid of the map to which one is aligning, e.g. using “vop resample x ongrid y” in Chimera. This step involves a certain degree of data loss, which is mostly insignificant but occasionally affects the quality of the resultant map in a way that is visually noticeable. Does anyone have any tips for minimizing this data loss, or is that impossible? E.g., if I oversample the map to which I am aligning by lets say 4 times, resample my map on that grid, and then save at gridstep 3 will that help, or is the data loss an unalterable consequence of the interpolation procedure? Best, Oliver.

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