CIS peptides

[Ashley Buckle]

We are trying to refine a CIS peptide bond (not Pro) by first patching 
it as CISP (as in the manual), but without success - XPLOR flips it to 
trans every time and we dont really understand how to solve this. Has 
anyone actually refined a protein structure with a CIS (non-Pro) 
peptide bond?

Thanks,  Ashley Buckle