Defining the Structural Basis for Allosteric Product Release from E. coli Dihydrofolate Reductase Using NMR Relaxation Dispersion.

ABSTRACT: The rate-determining step in the catalytic cycle of E. coli dihydrofolate reductase is tetrahydrofolate (THF) product release, which can occur via an allosteric or an intrinsic pathway. The allosteric pathway, which becomes accessible when the reduced cofactor NADPH is bound, involves transient sampling of a higher energy conformational state, greatly increasing the product dissociation rate as compared to the intrinsic pathway that obtains when NADPH is absent. Although the kinetics of this process are known, the enzyme structure and the THF product conformation in the transiently formed excited state remain elusive. Here, we use side-chain proton NMR relaxation dispersion measurements, X-ray crystallography, and structure-based chemical shift predictions to explore the structural basis o

SUBMITTER: Oyen D 

PROVIDER: S-EPMC5562155 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature