title: Analysis of the conformational profile of trishomocubane amino acid dipeptide.
abstract: 4-Amino-(D3)-trishomocubane-4-carboxylic acid is a constrained alpha-amino acid residue that exhibits promising conformational characteristics, i.e., helical and beta-turns. As part of the development of conformational guidelines for the design of peptides and protein surrogates, the conformational energy calculations on trishomocubane using molecular mechanics and ab initio methods are presented. The C(alpha) carbon of trishomocubane forms part of the cyclic structure, and consequently a peptidic environment was simulated with an acetyl group on its N-terminus and a methylamide group on its C-terminus. Ramachandran maps computed at the molecular mechanics level using the standard AMBER (parm94) force field libraries compared reasonably well with the corresponding maps computed at the Hartree Fock level, using the 6-31G* basis set. Trishomocubane peptide (Ac-Tris-NHMe) is characterized by four low energy conformers corresponding to the C7ax, C7eq, 3(10), and alpha(L) helical structures.
authors.affiliation: Department of Chemistry, Durban Institute of Technology, Steve Biko Campus, P.O. Box 1334, Durban, 4000, South Africa. bisettyk@dit.ac.za
authors.forename: Krishna
authors.initials: K
authors.lastname: Bisetty
authors.forename: Penny
authors.initials: P
authors.lastname: Govender
authors.forename: Hendrik G
authors.initials: HG
authors.lastname: Kruger
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation; D017434:Protein Structure, Tertiary; D012984:Software; D055672:Static Electricity; D014961:X-Ray Diffraction
chemical_list: C511220:4-amino-(D3)-trishomocubane-4-carboxylic acid; D000596:Amino Acids; D001704:Biopolymers; D001952:Bridged-Ring Compounds; D004151:Dipeptides; D002244:Carbon