Neutron crystallography of copper amine oxidase reveals keto/enolate interconversion of the quinone cofactor and unusual proton sharing.

ABSTRACT: Recent advances in neutron crystallographic studies have provided structural bases for quantum behaviors of protons observed in enzymatic reactions. Thus, we resolved the neutron crystal structure of a bacterial copper (Cu) amine oxidase (CAO), which contains a prosthetic Cu ion and a protein-derived redox cofactor, topa quinone (TPQ). We solved hitherto unknown structures of the active site, including a keto/enolate equilibrium of the cofactor with a nonplanar quinone ring, unusual proton sharing between the cofactor and the catalytic base, and metal-induced deprotonation of a histidine residue that coordinates to the Cu. Our findings show a refined active-site structure that gives detailed information on the protonation state of dissociable groups, such as the quinone cofactor, which are

SUBMITTER: Murakawa T 

PROVIDER: S-EPMC7245091 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature