CHAPERONE-ASSISTED PROTEIN-FOLDING

Molecular chaperones of the Hsp70 and chaperonin families are basic co nstituents of the cellular machinery that mediates protein folding. Re cent functional and structural studies corroborate existing models for the mechanism of these components. Highlights of the past year includ e the X-ray crystallographic analysis of the peptide-binding domain of the Escherichia coli Hsp70 homolog, DnaK, the direct demonstration of protein folding in the central cavity of the chaperonin GroEL, and th e visualization of conformational changes in GroEL during the chaperon in folding cycle.