Generalized-ensemble simulations in protein science

In simulations in materials and biological sciences, one encounters with a great difficulty that conventional simulations will tend to get trapped in states of energy local minima. A simulation in generalized ensemble performs a random walk in potential energy space and can overcome this difficulty. From only one simulation run, one can obtain canonical-ensemble averages of physical quantities as functions of temperature by the histogram reweighting techniques. We review thegeneralized-ensemble algorithms. The multidimensional extensions of the replica-exchange method and simulated tempering are presented. The effectiveness of the methods is tested with short peptide and protein systems.