Stoichiometry and thermodynamics of the interaction between the C-terminus of human 90Â kDa heat shock protein Hsp90 and the mitochondrial translocase of outer membrane Tom70

► The interaction of human proteins C-Hsp90 and Tom70 was studied by biophysical tools. ► One monomer of Tom70 binds a dimer of C-Hsp90 with a KD of 360 ± 30 nM. ► Tom70 has a high affinity for C-Hsp90 in comparison to other TPR proteins.