Conformational effects of one glycine residue on the other glycine residues in the Ac-Gly-Gly-Gly-NHMe tripeptide motif: an ab initio exploratory study

Ab initio molecular computations were carried out on the tripeptide model, Ac-Gly-Gly-Gly-NHMe at the RHF/3-21G ab initio level of theory. Two of the glycine residues were chosen at a time to be in the fully extended, or β (C5) conformation, in order to monitor the effects on the third residue with varying the backbone conformation. The topologies of each of the three Ramachandran type conformational potential energy surfaces were analyzed and five minima (β, γl, γd, δl, δd) associated with each one of the three glycine residues, were located for each surface.