On Unsatisfied Hydrogen Bonds in the N-Terminal Subdomain of Villin Headpiece

Villin headpiece is a small autonomously folding protein that has emerged as a model system for understanding the fundamental tenets governing protein folding. In this communication, we employ NMR and X-ray crystallography to characterize a point mutant, H41F, which retains actin-binding activity, is more thermostable but, interestingly, does not exhibit the partially folded intermediate observed of either wild-type or other similar point mutants.