[chimerax-users] Coloring pdb surface by different colors

[Elaine Meng]

Hi Yaikhomba,
You do not need to use molmap. You can use the "volume mask" command to mask a volume with any surface, including a molecular surface.

<http://rbvi.ucsf.edu/chimerax/docs/user/commands/volume.html#mask>

I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On Nov 27, 2020, at 3:03 AM, Y. Mutum <ym337 at cam.ac.uk> wrote:
> 
> Hi Elaine
> 
> Thanks - this works.
> On a similar note, I was thinking if we can use this surface (generated from the surface command using a pdb) to cave out the volume that this surface encloses within a cryo-EM map. The other complementary part as well would be helpful - the volume outside this surface (but enclosed within the cryo-EM map).
> 
> I thought of the 'vop subtract' command but it requires 2 volumes and I am not sure how I can use the surface to subtract. Also, the surface generated does not seem to have a model number, so I am not sure where to start. 
> 
> I am not sure I want to use 'molmap' command using the pdb - it does not seem to overlap very well with the surface and depends on the resolution and the contour threshold specified.
> 
> Just to recap,
> 	• how do we use the surface (generated from the pdb) to cut out volumes from a cryo-EM map?
> 	• if we have to end up using a molmap command to subtract the volume from the cryo-EM map, what resolution (and contour threshold) of the volume would you suggest to have a 'surface' equivalent (which I think is the solvent-accessible surface).
> 
> Thanks
> Yaikhomba
> From: Elaine Meng <meng at cgl.ucsf.edu>
> Sent: 27 November 2020 00:05
> To: Y. Mutum <ym337 at cam.ac.uk>
> Cc: chimerax-users at cgl.ucsf.edu <chimerax-users at cgl.ucsf.edu>
> Subject: Re: [chimerax-users] Coloring pdb surface by different colors
>  
> Hi Yaikhomba,
> Definitely yes, you just need to specify the residue range in the "spec" (specifier) part of the  "color" command.  
> <http://rbvi.ucsf.edu/chimerax/docs/user/commands/color.html#simple>
> 
> As explained in that help page, to color only the molecular surface for those residues (not atomic sticks, ribbons, etc.) you would include the "target s" option.  For example, these commands would show molecular surface for 2gbp and color the parts of the surface orange for residues 50-100 and 126-135 in chain A:
> 
> open 2gbp
> surface
> color /A:50-100,126-135 orange target s
> 
> image of result attached.
> 
> This page explains command-line specification (how to specify parts of the structure instead of the whole structure):
> <http://rbvi.ucsf.edu/chimerax/docs/user/commands/atomspec.html>
> 
> I hope this helps,
> Elaine
> -----
> Elaine C. Meng, Ph.D.                       
> UCSF Chimera(X) team
> Department of Pharmaceutical Chemistry
> University of California, San Francisco
> 
> 
> <Screen Shot 2020-11-26 at 4.03.41 PM.png>
> 
>> On Nov 26, 2020, at 12:48 PM, Y. Mutum <ym337 at cam.ac.uk> wrote:
>> 
>> Hi
>> 
>> I have a pdb with 10 TMH (single polypeptide protein, so only 1 chain in pdb). The first TMH are colored in green and the rest in yellow.
>> Is there a way to create a surface that consists of both these colors? i.e. Surface corresponding to TMH's 1-5 is colored in green, while the surface corresponding to TMH's 6-10 in yellow?
>> 
>> I tried the surface command option but it seems to color the entire surface in a uniform color.
>> 
>> Any suggestions would be very helpful.
>> 
>> Thanks
>> Yaikhomba
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