[Chimera-users] Fusing or bonding two protein chains?!

[Elaine Meng]

Hi Maziar,
Yes -- it sounds like you already have the structures in the desired relative position.  In that case, you would next combine the two models into one model (which could change residue numbering or chain ID so that there will not be conflicts) and then add a bond.  The structures you open in Chimera should be separate PDB files, not one PDB file, because you want Chimera to do the combining and renumbering.  If you start with one PDB file there will already be conflicts.  You would open the two separate PDB files and then do the following:

Combining models.  Can be done with the "copy/combine" function in the right side of the Model Panel (open from Favorites menu), or with the command "combine"
<http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/combine.html>
<http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/modelpanel.html#functions>

Adding the bond.  Can be done with the "Adjust Bonds" section of Build Structure (in menu under Tools... Structure Editing) or the command "bond"
<http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html#bond>
<http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/bond.html>

However, if you did NOT already have the structures in the desired relative position, you could use the "Join Models" section of Build Structure to do all of the above: move one structure to form a bond of the specified geometry, combine the two into one model, and form the bond.  You might want to try that anyway... just make sure you have saved your previous positions, for example as a session, beforehand.
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

On Oct 15, 2010, at 11:49 AM, #MAZIAR SOLEYMANI ARDEJANI# wrote:

> Hello, All! 
> I have created a pdb file by putting two protein structures close to each other through rotation and translation; so that N-terminus of one is close to the C-terminus of the other. 
> I would like to link one protein's C-terminus to the other protein's N-terminus, i.e. to create a peptide bond between two protein chains and then save the fused protein structure as a pdb file with a single chain.
> 
> Is there a way to do this in chimera? Can Chemira reset atom numbers and the residue and chain names?
> Thanks in advance and best regards,
> Maziar S. Ardejani