Conformational features of human melanin-concentrating hormone: an NMR and computational analysis(574 views) Vitale RM, Zaccaro L, Di Blasio B, Fattorusso R, Isernia C, Amodeo P, Pedone C, Saviano M
Isto. Biostrutture Bioimmagini CNR, via Mezzocannone 6, 80134 Napoli, Italy
Dipartimento di Scienze Ambientali, Seconda Università di Nopoli, via Vivaldi 43, 81100 Caserta, Italy
Isto. di Chimica Biomolecolare CNR, via Campi Flegrei 34, 80070 Pozzuoli, Napoli, Italy
References: Not available.
Conformational features of human melanin-concentrating hormone: an NMR and computational analysis
The conformational features of human melanin-concentrating hormone (hMCH) [Asp1-Phe2-Asp3-Met4-Leu5-Arg6-cyclo(S[bond]S)(Cys7-Met8-Leu9-Gly10-Arg11-Val12-T yr13-Arg14-Pro15-Cys16)-Trp17-Gln18-Val19], in water and in a CD(3)CN/H(2)O (1:1 v/v) mixture at 298 K, have been determined by NMR spectroscopy followed by simulated annealing and molecular dynamics analyses to identify conformer populations. Backbone clustering analysis of NMR-spectroscopy-derived structures in the 7-16 peptide region led to the identification of a single representative structure in each solvent. Both root mean square deviation clustering and secondary structure analysis of the final conformers in both solvents show substantial convergence of most conformers into a single fold in the 4-17 region, with a limited variability around Gly10 and Tyr13 on going from CD(3)CN/H(2)O to pure water. The main feature deduced from the analysis of secondary structures is the occurrence of an N-terminal alpha helix of variable length, which spans an overall residue range of 2-9. A comparative analysis in the two solvents highlights that these structures are substantially different from that reported in the literature for the cyclic MCH(5-14) subunit of salmon MCH, which was used to perform a molecular characterization of the MCH/receptor complex. Our conformational data call for a critical revision of the proposed MCH/receptor complex model.
Conformational features of human melanin-concentrating hormone: an NMR and computational analysis