Referenced in: none

Automatically associated channels: Kir2.3

Title: Long, chiral polypeptide 3(10)-helices at atomic resolution.

Authors: A Bavoso, E Benedetti, B Di Blasio, V Pavone, C Pedone, C Toniolo, G M Bonora, F Formaggio, M Crisman

Journal, date & volume: J. Biomol. Struct. Dyn., 1988 Feb , 5, 803-17

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/3271490

Abstract
The crystal-state preferred conformation of the terminally blocked hepta- and octapeptides with the general formula -(Aib)n L-Leu-(Aib)2- (n = 4 and 5, respectively), determined by X-ray diffraction, was found to be a right-handed 3(10)-helix stabilized by five and six consecutive intramolecular NH...O = C H-bonds of the C(10)-III type, respectively. The octapeptide structure represents the first observation at atomic resolution of a regular, chiral 3(10)-helix larger than two complete turns. In both cases the right handed screw sense of the helix is dictated by the presence of the single, internal L-residue. This study confirms the propensity of short peptides rich in Aib, the prototype of the amino acid residues dialkylated at the alpha carbon, to adopt a 3(10)-helical structure and is expected to help our understanding of the conformational preferences of the membrane-active, channel-forming, ion-transporting peptaibol antibiotics.