Hello,
I have been modeling a homopentamer which should have a disulfide bond in each subunit in the same position as the multiple templates that we are using (the alignments have the cys residues of the target lined up with the disulfide-forming cys in the templates). When I carry out the alignment of the templates using salign, the XX_fit.pdb files for the templates do not have the disulfides indicated using SSBOND, even though the original pdb files (XX.pdb) do have the SSBOND lines in them.
I know that automodel will automatically include disulfide restraints if the templates have them. However,the returned models, while superimposing nicely on the template structure, do not have the disulfides, even though the cysteines in the model are right where the disulfide-forming cysteines are in the template. I assume that automodel uses the XX_fit.pdb files for the fitting routines, and the fact that the XX_fit.pdb files are missing the SSBOND lines is why the disulfides are present in the model.
Is this correct? Can I just edit the XX_fit.pdb files to include the SSBOND lines to force the model to have the disulfides?
Alternatively, I guess I could use model.patch as per node24 in the online manual to force the disulfides to be where I want them to be, but this just doesn't seem right if the templates all have the disulfide and the alignments have the cysteines where they should be.
Thanks
Mike White