The effect of substrates on the inter‐domain interactions of the hinge‐bending enzyme 3‐phosphoglycerate kinase

Abstract

A hinge-bending mechanism has been proposed for phosphoglycerate kinase, in which the two domains bend about the connecting “swaist& rsquo; region. In partially denaturing concentrations of guanidinium chloride the substrate 3-phosphoglycerate stabilises one domain against denaturation and destabilises the other. The reduction of mutual stabilisation of the two domains on binding substrate indicates a freeing of the hinge to allow the protein to take up other states rather than a directive mechanism. The stabilisation of both domains at higher concentrations of ATP at which the enzyme is inhibited supports this mechanism.