A MOLECULAR CLAMP IN THE CRYSTAL-STRUCTURE OF THE N-TERMINAL DOMAIN OF THE YEAST HSP90 CHAPERONE

Hsp90 is a highly specific chaperone for many signal transduction prot eins, including steroid hormone receptors and a broad range of protein kinases. The crystal structure of the N-terminal domain of the yeast Hsp90 reveals a dimeric structure based on a highly twisted sixteen st randed beta-sheet, whose topology suggests a possible 3D-domain-swappe d structure for the intact Hsp90 dimer. The opposing faces of the beta -sheets in the dimer define a potential peptide-binding cleft, suggest ing that the N-domain may serve as a molecular 'clamp' in the binding of ligand proteins to Hsp90.