title: Experimental studies and potential energy calculations of the blocked tetrapeptide Ac-Lys-Pro-Gly-Ile-NMA from the third loop of short-chain snake venom neurotoxins.
abstract: The conformational space of the tetrapeptide Ac-Lys-Pro-Gly-Ile-NMA from the beta-bend present in the third loop of short-chain snake venom neurotoxins was investigated with the aid of energy calculations, resulting in the identification of an ensemble of beta-turn conformations. These results were compared with the experimentally determined conformations, as observed using NMR and CD spectroscopy. A random coil conformation of the peptide is indicated in polar hydrogen-bonding solvents. In less polar solvents the peptide backbone assumed a more rigid conformation, as reflected by the existence of at least a type II beta-turn conformation.
authors.affiliation: Department of Chemistry, University of Pretoria, South Africa.
authors.forename: H M
authors.initials: HM
authors.lastname: Roos
authors.forename: P H
authors.initials: PH
authors.lastname: Van Rooyen
authors.forename: P L
authors.initials: PL
authors.lastname: Wessels
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D012910:Snake Venoms / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009498:Neurotoxins; D009842:Oligopeptides; D012910:Snake Venoms