Monte-Carlo calculations of the solvent effects on the conformation of angiotensin II.
An efficient Metropolis Monte-Carlo (MMC) procedure is proposed in order to calculate averages of the energy of conformation and structural properties of a polypeptide chain in interaction with a solvent. The contribution of hydration to the free energy of conformation of the macromolecule is calculated using the accessible surface area method. This algorithm, performed with different sets of atomic solvation parameters (ASP), is applied to the peptidic hormone angiotensin II. Different situations of solvation of that molecule are described when the ASP of the polar atoms are fixed to 0, whereas those of the apolar atoms are given values varying from -1.0 to 1.0. From results thus obtained, transitions from extended to collapsed conformations of the polypeptide chain can be simulated. Such changes of conformation could be related to a possible mechanism of binding of this hormone on a membrane surface.
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Laboratory of Molecular Biophysics, URA CNRS 494, H. Poincaré-Nancy 1 University, Faculty of Sciences, Vandoeuvre les Nancy, France.
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D000804:Angiotensin II / Q000737:chemistry*; D009010:Monte Carlo Method; D011487:Protein Conformation; D012997:Solvents
D012997:Solvents; D000804:Angiotensin II