In this paper we present a computationally efficient means of performing simulated annealing on atomic level protein structures. The method which is based upon a Trotter factorization of the classical Liouville propagator is employed in a series of simulated annealing studies of a small protein using a standard molecular mechanics type potential as well as a continuum approximation to include the effects of solvation. Preliminary results are presented for the performance of the potential using standard force field parametrizations in attempts to distinguish native-like structures from those that are distinctly non-native. Low-energy structures with large rms deviations from the minimized X-ray structure were found, thereby suggesting the possibility that the potentials employed in this work may not be of sufficient accuracy to distinguish the native protein structure.