Making a network of hydrophobic clusters.

The early events in protein folding are often difficult to track. A hydrophobic collapse, during which nonpolar residues are buried away from the polar solvent, has been proposed, but little is known about the role of this collapse in protein folding. In his Perspective, Baldwin discusses the report by Klein-Seetharaman et al., who shed some light on this issue. A network of hydrophobic clusters stabilizes at least one nonnative interaction in unfolded hen lysozyme. In conjunction with earlier studies, the results suggest that this network has a beneficial effect on the folding of the protein.