title: Conformational space comparison of GnRH and lGnRH-III using molecular dynamics, cluster analysis and Monte Carlo thermodynamic integration.
abstract: The conformational space available to GnRH and lGnRH-III was compared using 5.2 ns constant temperature and pressure molecular dynamics simulations with explicit TIP3P solvation and the AMBER v. 5.0 force field. Cluster analysis of both trajectories resulted in two groups of conformations. Results of free energy calculations, in agreement with previous experimental data, indicate that a conformation with a turn from residues 5 through 8 is preferred for GnRH in an aqueous environment. By contrast, a conformation with a helix from residues 2 through 7 with a bend from residues 6 through 10 is preferred for lGnRH-III in an aqueous environment. The side chains of His2 and Trp3 in lGnRH-III occupy different regions of phase space and participate in weakly polar interactions different from those in GnRH. The unique conformational properties of lGnRH-III may account for its specific anti cancer activity.
authors.affiliation: Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Watts
authors.forename: M
authors.initials: M
authors.lastname: Mezei
authors.forename: R F
authors.initials: RF
authors.lastname: Murphy
authors.forename: S
authors.initials: S
authors.lastname: Lovas
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D003198:Computer Simulation; D007987:Gonadotropin-Releasing Hormone / Q000737:chemistry*; D007798:Lampreys; D008958:Models, Molecular; D009010:Monte Carlo Method; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D007987:Gonadotropin-Releasing Hormone