  We have used computer simulation to study the collapse of a hydrophobic chain
in water. We find that the mechanism of collapse is much like that of a first
order phase transition. The evaporation of water in the vicinity of the polymer
provides the driving force for collapse, and the rate limiting step is the
nucleation of a sufficiently large vapor bubble. The study is made possible
through the application of transition path sampling and a coarse grained
treatment of liquid water. Relevance of our findings to understanding the
folding and assembly of proteins is discussed.
