  We describe optimized parallel tempering simulations of the 46-residue
B-fragment of protein A. Native-like configurations with a root-mean-square
deviation of approximately 3A to the experimentally determined structure
(Protein Data Bank identifier 1BDD) are found. However, at biologically
relevant temperatures such conformations appear with only about 10% frequency
in our simulations. Possible short comings in our energy function are
discussed.
