Activity Regulation of a Glutamine Amidotransferase Bienzyme Complex by Substrate-Induced Subunit Interface Expansion.

ABSTRACT: Glutamine amidotransferases are multienzyme machineries in which reactive ammonia is generated by a glutaminase and then transferred through a sequestered protein tunnel to a synthase active site for incorporation into diverse metabolites. To avoid wasteful metabolite consumption, there is a requirement for synchronized catalysis, but any generally applicable mechanistic insight is still lacking. As synthase activity depends on glutamine turnover, we investigated possible mechanisms controlling glutaminase catalysis using aminodeoxychorismate synthase involved in folate biosynthesis as a model. By analyzing this system in distinct states of catalysis, we found that incubation with glutamine leads to a subunit interface expansion by one-third of its original area. These changes completely e

SUBMITTER: Funke FJ 

PROVIDER: S-EPMC7617670 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature