Affiliations: Dipartimento di Chimica, Universita di Napoli Federico II, Napoli 80126, Italia.
Centro di Studio per la Chimica del Farmaco del CNR, Università di Roma La Sapienza, Roma, Italy
Department of Chemistry, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Naples, Italy
References: Not available.
Conformation and calcium-binding properties of a bicyclic nonapeptide
The conformation and calcium binding properties of the bicyclic nonapeptide BCP2, cyclo-(Glu1-Ala2-Pro3-Gly4-Lys5-Ala6-Pro7-Gly8)-cyclo-(1gammafwdarw5epsi lon) Gly9, have been investigated by means of NMR spectroscopy. Interproton distances, evaluated by nuclear Overhauser effect (NOE) contacts, and phi angles, from 3JNH-alphaCH, have been used to obtain a feasible model for the BCP2-Ca2+ (BCP: bicyclic peptide) complex by means of restrained molecular dynamics (RMD). The NMR analysis of the free peptide, carried out in CD3CN, shows the presence in solution of at least four conformers in intermediate exchange rate. The addition of calcium ions caused the appearance of a new set of resonances, differing from those observed for the free BCP2. A comparison with published data about the conformational behavior of the closely analogous peptide BCP3, differing from BCP2 for two Leu residues instead of two Ala residues in positions 2 and 6, shows that this simple substitution dramatically increases the peptide flexibility. On the contrary, upon calcium ion addition, both BCP2 and BCP3 reach a strictly close conformation, as strongly testified by the almost identical 1H-NMR spectra exhibited by both peptides. The RMD molecular model of the BCP2-Ca2+ complex, here reported, is a quite symmetric structure, presenting a three-dimensional cavity ideal for the binding of spherical cations. Four carbonyls from the main ring (Ala2, Gly4, Ala6 and Gly8) point toward it, offering, together with the two carbonyls of the peptide bridge (Gly9 and gammaGlu1), putative coordinations to the cation.
Conformation and calcium-binding properties of a bicyclic nonapeptide
Kállay C, Dávid A, Timári S, Nagy EM, Sanna D, Garribba E, Micera G, De Bona P, Pappalardo G, Rizzarelli E, Sóvágó I * Copper(II) complexes of rat amylin fragments(517 views) Dalton T (ISSN: 1477-9234, 1477-9226, 1477-9234electronic), 2011 Oct 14; 40(38): 9711-9721. Impact Factor:3.838 ViewExport to BibTeXExport to EndNote
Aloj L, Aurilio M, Rinaldi V, D'Ambrosio L, Tesauro D, Peitl PK, Maina T, Mansi R, Von Guggenberg E, Joosten L, Sosabowski JK, Breeman WA, De Blois E, Koelewijn S, Melis M, Waser B, Beetschen K, Reubi JC, De Jong M * The EEE project(545 views) Proc Int Cosm Ray Conf Icrc Universidad Nacional Autonoma De Mexico, 2007; 5(HEPART2): 977-980. Impact Factor:0 ViewExport to BibTeXExport to EndNote