Optimization Methods for a Boltzmann-Weighted Mean
نویسندگان
چکیده
An optimization protocol is proposed that combines a mean field simulation approach with Boltzmann-weighted sampling. This is done by including Boltzmann probabilities of multiple conformations in the optimization procedure. The method is demonstrated on a simple model system and on the side-chain conformations of phenylalanines in a small hexapeptide. For comparison, calculations were performed using classical stochastic dynamics simulations [ M . Saunders, K. N . Houk, Y. Wu, C. Still, M. Lipton, G. Chang, and W. C. Guida (1990), Journal of the American Chemical Society, Vol. 12, pp. 141 91, iterative optimization of probabilities on a j x e d set ofbasis conformations [ P. Koehl and M. Delaure (1994), Journal of Molecular Biology, Vol. 239, pp. 249-2751, and simulations with locally enhanced sampling [A. Roitberg and R. Elber ( I 991), Journal of Chemical Physics, Vol. 95, pp. 9277-92871. Although approximations are used in our method, the results may be more physically meaningfiul than those of the other procedures discussed. Furthermore, the approximate Boltzmann distribution allows generalization of the results.
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