[Chimera-users] Molecular weight of an EM map

[Tom Goddard]

Hi Pu,

   Use the "Measure Volume and Area" dialog under menu Tools / Volume 
Data to show the volume in cubic Angstroms enclosed by your map contour 
surface.  It will update automatically as the threshold changes.  Make 
sure the voxel size of your map is set correctly in Angstroms because 
the reported enclosed volume uses that.  That is set in the Volume 
Viewer dialog under the Coordinates panel.  To estimate molecular weight 
from the volume you could use an approximate value for globular proteins 
from the literature of 1.21 cubic Angstroms per Dalton (Harpaz 1994).

     
http://www.cgl.ucsf.edu/chimera/tutorials/eman07/chimera-eman-2007.html#part2

   Tom

> Hi Tom,
>
> I have a question to ask you.
>
> I'm working on a 3D EM map from single particle reconstuction using Chimera. I
> would like to know the total volumn of this 3D model or its molecular weight
> when I change thresholds. How can I do it or where can I find this value?
>
> Best regards
>
>
> Pu Qian