Single-Ring Intermediates In The Catalytic Cycle Of The Human Mitochondrial Hsp60

The human mitochondrial heat shock protein 60 (hsp60) is composed to two heptameric rings stacked back-to-back. During the protein-folding cycle, these two rings dissociate to form single-ring intermediates that are catalytically active in-vitro and in-vivo. In this book chapter, we discuss the structural and catalytic features of hsp60 single-ring intermediates. We also provide a comparative analysis of the structural and mechanistic characteristics of single-ring intermediates observed in hsp60 versus phi-EL, OBP, and groEL chaperonin complexes that have also been reported to utilize single-rings within their catalytic cycle.