Computational Chemistry and Molecular Modeling
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Molecular dynamics simulations out to 100 ps have been carried out at 300 K in vacuo on the repeating pentapeptide, (VPGVG), of the elastin fiber. The structure employed in the simulation is a β-spiral (helical structure) with 2.7 pentamers per turn and with a 9.45 Å rise per turn and 21.6 Å rise per turn in the relaxed and extended states, respectively. Large amplitude backbone torsion angle fluctuations are observed in the relaxed state, and significant damping is observed upon extension, particularly in the suspended segments of the β-spiral structure. Accordingly the entropy change an extension was computed and found to be a substantial -1.1 entropy units per residue. The various energy components are compared for relaxed and extended states and the relevance of the results to the molecular mechanism of entropic elasticity is discussed.
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