Unfolded in vacuo lysozyme folds into native, quasinative, and compact structures.

We show that the relaxation dynamics of unfolded in vacuo lysozyme is not random. Analyses of molecular dynamics trajectories in a convenient space of molecular shape descriptors reveal a ``favored'' pattern of transitions leading to stable conformations. The relaxation paths exhibit a balanced change in shape features: globular spheroids are formed slowly enough to allow the proper entanglement of secondary-structural elements. The present study shows that a protein in vacuo can actually (re)fold into native and quasinative structures. The driving force for these transformations is intrinsic to the polypeptide chain.