- Chimera-users - RBVI Mailing Lists

local cross-correlation coefficient
by 李智海 09 Jul '14

09 Jul '14

Hi, I performed tool "Fit in map” to calculate the correlation value, i was wondering whether the value is the same as local cross-correlation coefficient (local CCC). Thanks in advance for your help! Best wishes for you! Zhihai Li

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Chimera Using Problem
by christophe 08 Jul '14

08 Jul '14

Hi,I'm trying to import chimera in python but when i try to make it i've bug, it said to me the following thing just after have execute:>>>from chimera import *Traceback (most recent call last): File "C:\Python27\Lib\site-packages\Chimera 1.9\share\testMM.py", line 1, in <module> from chimera import * File "C:\Python27\Lib\site-packages\Chimera 1.9\share\chimera\__init__.py", line 16, in <module> from _chimera import BBox, Camera, Color, ColorGroup, DirectionalLight, LODControl, Lens, LensViewer, Light, Material, MaterialColor, Model, NoGuiViewer, OGLFont, OSLAbbreviation, OpenModels, OpenState, PathFinder, PixelMap, Plane, Point, PositionalLight, Selectable, SharedState, SpotLight, Sphere, Texture, TextureColor, TrackChanges, Vector, Viewer, X3DScene, XformImportError: No module named _chimeraI'm on windows 8 64 bits and i have chimera 1.9 and python 2.7.7 i've this following structure of directories:C:\Python27\Lib\Site-packages\chimera 1.9And i've run my script under the python.exe of chimera.So can you said to me what is wrong to fix it cause of i need chimera to made a script using superposition ( so with MatchMaker)? Cordially,Christophe Linhard.

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Suggestion - secondary structural element as an additional level in the selection hierarchy?
by Oliver Clarke 07 Jul '14

07 Jul '14

Greetings, Currently, the selection hierarchy in Chimera is as follows - atom<residue<chain<model<all. I don’t know how complicated it would be to implement, but perhaps it might be desirable in a future version of Chimera to include “secondary structural element” (being coil, helix or strand) as an additional level, between residue and chain? This would enable easy/quick selection/coloring of specific loops, helices or strands in a structure. E.g, say I am working on a helical repeat protein like an importin, and I want to color all the helices on the concave, inside surface one color, and all the helices on the outside surface another color - to do that at present is possible, but somewhat laborious, as it is necessary to explicitly specify the boundaries of each helix, and if there are many helices in the desired selection that are not sequence-adjacent then this becomes complicated. If SSE was a level of the selection hierarchy, I could select one residue in each helix on the desired surface, press the up arrow once to broaden the selection and all the helices on the inner surface would then be selected, without needing to know the location in the sequence of each helix. It seems like there would be quite a lot of use cases where this might save time - selecting individual surface exposed loops, or a specific set of helices or strands that form a binding surface for a ligand or partner protein, for example. Best regards, Oliver.

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Change default display settings?
by rswett＠chem.wayne.edu 07 Jul '14

07 Jul '14

Hi, I was wondering if there was a way to change my startup preferences so that the default is to show only ribbons? No atoms?

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How to install chimera as a python module
by Ivan Castro 07 Jul '14

07 Jul '14

Hi everyone, Looks like Chimera can be installed as a python module, but I can't find the first steps to do that. Anyone can suggest me a tutorial or webpage for this purpose. Thanks. -- Iván Castro, B. Sc (Hons). M. Sc Student - Biology at Universidad del Valle, Colombia. Member of Grupo de Estudios en Genética, Ecología Molecular y Fisiología Animal. Member of Fundación Colombiana para la Investigación y Conservación de Tiburones y Rayas.

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how to connect broken ribbon
by Pu Qian 07 Jul '14

07 Jul '14

Hi there, Sometime, when I use chimera to make a ribbon presentation of protein, the helix region will either broken or does not present properly. Similar thing can be happened in Pymol. But, Pymol provides a command called "alter". When I rebuilt it after altering, broken helix can be repaired. I'm wondering is there similar function in Chimera, or is there a suitable method which can be used to deal with it. Thanks Best regards Pu Qian

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Measure correlation for rotated map positions
by Tom Goddard 03 Jul '14

03 Jul '14

Hi Rakesh, The “measure correlation” rotationAxis option only accepts a specification of two atoms to define the rotation axis. This is explained in the Chimera documentation. http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#correlat… Specifying 3 numbers is not enough since you need both a direction and a point on the axis. If you have a center x,y,z position and axis vector ax,ay,az then you could use the “turn” command to do the rotations and the “measure correlation” command without the rotationAxis option as follows. perframe "turn 0,0,1 10 center 0,0,0 coord #1 model #1 ; measure corr #0 #1" frames 36 This does a rotation by 10 degrees about center 0,0,0 and axis 0,0,1 using map #1 coordinates then measures the correlation between map #1 and #0, repeating this 36 times (covering 360 degrees). Results are reported in the reply log. Tom On Jul 3, 2014, at 2:56 PM, Rakesh Ramachandran wrote: > Hi, > > I wanted to know how can I measure correlation starting from a fit and rotating the model around an axis with respect to the map. I tried calculating the centroid of the model and then rotate it using measure correlation but it did not work, the rotationAxis field was not taking the x,y,z position of the centroid of the model. > > Regards > Rakesh

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Structure editing
by George Tzotzos 02 Jul '14

02 Jul '14

I’m dealing with a X-ray model in which some of the residues are shown in two conformations. Is it possible to edit the structure keeping the higher occupancy conformation ONLY? Another question is whether it is possible to delete all waters but the selected ones (e.g. HOH molecules in the binding pocket that are conserved). I’ve been doing this manually using an editor and I wonder if there is better way of doing this. Thanks in advance for your advice Regards George

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suggested improvements
by Dougherty, Matthew T 02 Jul '14

02 Jul '14

1) first suggestion on the sym command the following is defined icosahedral symmetry I[,orientation] around center Example: i,n25 where orientation can be: 222 (default) - with two-fold symmetry axes along the X, Y, and Z axes 2n5 - with two-fold symmetry along X and 5-fold along Z n25 - with two-fold symmetry along Y and 5-fold along Z 2n3 - with two-fold symmetry along X and 3-fold along Z 222r - same as 222 except rotated 90° about Z 2n5r - same as 2n5 except rotated 180° about Y n25r - same as n25 except rotated 180° about X 2n3r - same as 2n3 except rotated 180° about Y In the chimera tool->higher order structure -> the icosahedral structure it defines similar orientations, assume in the same order. It would be helpful on the selections to include the sym syntax as part of the icosahedral structure text ie {222} xyz 2 fold {2n5} x 2 fold z 5 fold 2) second suggestion When reading an MRC file I occasionally see situations that make me question whether the file is EMDB complaint. It would be good to have the means to dump the MRC header, even if chimera refuses to read the file in its entirety. Matthew Dougherty National Center for Macromolecular Imaging Baylor College of Medicine ===========================================================================

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Re: [Chimera-users] Attaching a Probe to Modify an Existing Amino Acid
by Eric Pettersen 02 Jul '14

02 Jul '14

Hi Shana, Well, you might be able to get away with just setting that atom's "name" attribute to "SD", but since you are writing Python code anyway and residues hold their atoms in a name-indexed structure, it would be better to do it the right way by removing the atom from the residue, renaming it, and putting it back. Assuming you have the CYS residue in a variable named 'cys': s = cys.findAtom("SG") cys.removeAtom(s) s.name = "SD" cys.addAtom(s) --Eric On Jun 19, 2014, at 11:25 AM, Shana Burstein <sburstei(a)haverford.edu> wrote: > Hi Eric, > I was able to move the CN atoms from the CN residue to the CYS residue and call it MSCN. I actually need it to be called MSCN in order for the modified residue to be recognized by a force field in an MD simulation. My only problem now is that the S atom of cysteine is labeled as "SG" and I need it to be called "SD." I know how to do this by going through the Tool menu, but is there a way to automate that? > > Thanks, > Shana > > > On Wed, Jun 18, 2014 at 2:35 PM, Eric Pettersen <pett(a)cgl.ucsf.edu> wrote: > Hi Shana, > If you were starting from scratch, the procedure to add the CN would probably be simpler by using chimera.molEdit.addDihedralAtom() to add the C and then the N at the appropriate bond length, angle and dihedral and then rename the residue with: r.type = "MSCN". Nonetheless, you have come a long way down the road with your script and probably would not prefer to start over from scratch! So let's suppose you have your two relevant Residue instances in variables named 'cys' and 'cn'. The code to do what you want would be: > > for a in cn.atoms: > cn.removeAtom(a) > cys.addAtom(a) > cys.type = "MSCN" > # empty residues are problematic in various parts of Chimera, so... > cn.molecule.deleteResidue(cn) > > If you don't know how to get the 'cys' and 'cn' variables but you know an atom specifier that selects each, you can use this code to set the variables: > > runCommand("sel atom-spec-for-cys") > cys = chimera.selection.currentResidues()[0] > runCommand("sel atom-spec-for-cn") > cn = chimera.selection.currentResidues()[0] > > There's a couple of further relevant things here. Strictly speaking, 4-letter residue names are not legal in PDB format (while there is a column where a 4th character could go, according to the format definition that column is supposed to be blank). Therefore if you export your modified structure to other software programs, they may or may not be able to handle the 4-character residue name without problems. Therefore I recommend you use the same residue name that the PDB uses for this moiety, 4CY (which can be found in the 3or0 entry). > Along the same lines, 4CY can actually be found in the SwissSidechain rotamer library plugin for Chimera (SwissSidechain - A database of non-natural side chains) and therefore if you install that plugin then the entire substitution process becomes a single command: swapnaa 4CY cysteine-atom-spec. > > --Eric > > Eric Pettersen > UCSF Computer Graphics Lab > http://www.cgl.ucsf.edu > > On Jun 18, 2014, at 6:50 AM, Shana Burstein <sburstei(a)haverford.edu> wrote: > >> Hello, >> I am an undergraduate student at Haverford College and I am attempting to attach thiocyanate probes onto different sites along a protein by first replacing the existing amino acid with a cysteine and then by adding a C and N onto the S- of the Cys residue. I know it is possible to carry this out manually using Tools>Structure Editing>Modify Structure, but I am hoping to automate this process by calling an external .py script that will primarily contain a list of preexisting Chimera commands. >> >> I have been successful at converting the targeted amino acid to Cys using "swapaa," building a CN residue called MSCN (using the createMolecule.py as a guide), combining the two models into one ("combine selected close True") and forming a bond between the Cys S and CN C atoms ("bond"). >> >> At this point, I am seeking help in automating the renaming of the modified residue to MSCN. Currently, Chimera sees this residue as two different separate residues called CYS and MSCN. Is there a way to combine these two structures so that the label corresponds to MSCN and the residue number corresponds to CYS? >> >> Sincerely, >> >> Shana Burstein >> Haverford College '15 >> _______________________________________________ >> Chimera-users mailing list >> Chimera-users(a)cgl.ucsf.edu >> http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users > > > >

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