title: Comprehensive structural characterization of the cyclic disulphide-bridged nonapeptides, Arg- and Lys-conopressins.
abstract: Arg-conopressin-S and Lys-conopressin-G are cyclic disulphide-bridged nonapeptides isolated from the venom of cone snails. We performed a comprehensive conformational analysis for the cis and trans isomers of these conopeptides, in order to identify their characteristic structural and conformational features. In the course of our theoretical study, the Phi-Psi and chi(1) conformational spaces were explored in detail and the conformational distributions were compared to each other. For both cis and trans isomers of conopressins, the characteristic secondary structural elements and intramolecular H-bonds were identified. Our results pointed out that various turn structures stabilized by typical intramolecular H-bonds could be observed in the conformers of these conopeptides. Comparing the different conformational features of the cis and trans isomers of conopressins disclosed that several of them could be found for both isomers, however, structural properties characteristic for only the cis or trans isomer were also identified. Altogether, our comprehensive conformational study provided a detailed description of the three-dimensional (3D) structure of both conopressins.
authors.affiliation: Institute of Biophysics, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Janzsó
authors.forename: Gábor
authors.initials: G
authors.lastname: Rákhely
authors.forename: Balázs
authors.initials: B
authors.lastname: Leitgeb
mesh_terms: D000818:Animals; D003198:Computer Simulation; D004220:Disulfides / Q000737:chemistry*; D006860:Hydrogen Bonding; D009842:Oligopeptides / Q000737:chemistry*; D010121:Oxytocin / Q000031:analogs & derivatives* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D004220:Disulfides; D009842:Oligopeptides; D010456:Peptides, Cyclic; C076621:conopressin G; D010121:Oxytocin