BOVINE ADRENODOXIN - A MITOCHONDRIAL IRON-SULFUR PROTEIN - BINDS TO CHAPERONIN GROEL

The interaction of bovine adrenodoxin with the chaperonin GroEL was in vestigated using sucrose density centrifugation and analytical ultrace ntrifugation. It could be clearly established that denatured mature ad renodoxin comigrated in a sucrose density gradient with the GroEL olig omer, indicating that a complex had been formed. Up to 2 moles of adre nodoxin/mol GroEL can be bound. From the partial concentrations, assoc iation constants of 4.3 . 10(5) M(-1) for the first adrenodoxin molecu le and of 1.08 . 10(5) M(-1) for the second molecule to the complex, r espectively, were calculated. Upon addition of the cochaperonin GroES and Mg-ATP to the adrenodoxin-GroEL complex, adrenodoxin was released, indicating a specific binding between GroEL and adrenodoxin. (C) 1995 Academic Press, Inc.