each subunit of hsp60 has three domains: the apical domain, the equatorial domain, and the intermediate domain. the equatorial domain contains the binding site for atp and for the other heptameric ring. the intermediate domain binds the equatorial domain and the apical domain together. the intermediate domain induces a conformational change when atp is bound allowing for an alternation between the hydrophilic and hydrophobic substrate binding sites. in its inactive state, the protein is in a hydrophobic state. when activated by atp, the intermediate domain undergoes a conformational change that exposes the hydrophilic region. this insures fidelity in protein binding. chaperonin 10 aids hsp60 in folding by acting as a dome-like cover on the atp active form of hsp60. this causes the central cavity to enlarge and aids in protein folding. see the above figure for further detail on the structure.