Hi Folks, I am trying to add a four amino acid segment to the N-terminus of a protein in the pdb. I can generate the four residue stretch and move its C-term close to the N-term of the structured protein. I can then select the C' and N atoms, which are about 1.0 Angstrom apart. At that point, I am stuck. Not sure how to add a bond and then create a proper structure. I've played around with Join Models, but no luck. Without a peptide bond recognized by Chimera, ribbons are discontinuous. Any ideas? Many thanks, glenn Glenn L. Millhauser Department of Chemistry & Biochemistry UC Santa Cruz Santa Cruz, CA 95064 831 459 2176 voice 831 566 3337 cell 831 459 2935 fax 831 824 4645 google voice glennm@ucsc.edu http://chemistry.ucsc.edu/~glennm http://www.chemistry.ucsc.edu/faculty/millhauser.html