Site-Specific Tryptophan Labels Reveal Local Microsecond-Millisecond Motions of Dihydrofolate Reductase.

ABSTRACT: Many enzymes are known to change conformations during their catalytic cycle, but the role of these protein motions is not well understood. Escherichia coli dihydrofolate reductase (DHFR) is a small, flexible enzyme that is often used as a model system for understanding enzyme dynamics. Recently, native tryptophan fluorescence was used as a probe to study micro- to millisecond dynamics of DHFR. Yet, because DHFR has five native tryptophans, the origin of the observed conformational changes could not be assigned to a specific region within the enzyme. Here, we use DHFR mutants, each with a single tryptophan as a probe for temperature jump fluorescence spectroscopy, to further inform our understanding of DHFR dynamics. The equilibrium tryptophan fluorescence of the mutants shows that e

SUBMITTER: Vaughn MB 

PROVIDER: S-EPMC7503464 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature