Dear all, i'm trying to minimize a peptide (Tools, Structure editing, Minimize Structure) but I obtain this error message: No MMTK name for atom "H" in standard residue "GLY". I have a Gly in position 1, does this depends on the NH protonation? Also, I fixed most of the residues, including Gly 1, trying to minimize a small region (Fixed Atoms: selected, in minimize panel) but still have the same errors. How can I solve it? Thanks for your help, Best Marco -- Dr Marco Sette, PhD. Department of Chemical Sciences and Technology University of Rome, "Tor Vergata" via della Ricerca Scientifica, 00133, Rome, Italy e-mail: sette@uniroma2.it Tel.: +39-0672594424 -- Questa email รจ stata esaminata alla ricerca di virus dal software antivirus Avast. www.avast.com