Dear you all I have a modified peptide. The N atom of the first Glycine is replaced by an C atom, and it makes covalent bonds to the N atom of the fourth amino acid through a -C=C-C- linker. In case I didn't make it clear, here is a simple illustration:
.....(CO-Ca-C)-C=C-C-N........ (N belongs to the 4th residue) 1st Glycine Could anyone help me to define the LINK record in the hearder of the PDB file or whatever restraints or whatever library needed for carrying out refinement with Refmac5? I have been playing around for a while and got no success. Thanks in advance! Jie Liu