Structural Characterization of Early Michaelis Complexes in the Reaction Catalyzed by (+)-Limonene Synthase from Citrus sinensis Using Fluorinated Substrate Analogues.

ABSTRACT: The stereochemical course of monoterpene synthase reactions is thought to be determined early in the reaction sequence by selective binding of distinct conformations of the geranyl diphosphate (GPP) substrate. We explore here formation of early Michaelis complexes of the (+)-limonene synthase [(+)-LS] from Citrus sinensis using monofluorinated substrate analogues 2-fluoro-GPP (FGPP) and 2-fluoroneryl diphosphate (FNPP). Both are competitive inhibitors for (+)-LS with K_I values of 2.4 ± 0.5 and 39.5 ± 5.2 μM, respectively. The K_I values are similar to the K_M for the respective nonfluorinated substrates, indicating that fluorine does not significantly perturb binding of the ligand to the enzyme. FGPP and FNPP are also substrates, but with dramatically reduced

SUBMITTER: Kumar RP 

PROVIDER: S-EPMC5642273 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature