A closer look at the spectroscopic properties of possible reaction intermediates in wild-type and mutant (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase.

ABSTRACT: (E)-4-Hydroxy-3-methylbut-2-enyl diphosphate reductase (IspH or LytB) catalyzes the terminal step of the MEP/DOXP pathway where it converts (E)-4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP) into the two products, isopentenyl diphosphate and dimethylallyl diphosphate. The reaction involves the reductive elimination of the C4 hydroxyl group, using a total of two electrons. Here we show that the active form of IspH contains a [4Fe-4S] cluster and not the [3Fe-4S] form. Our studies show that the cluster is the direct electron source for the reaction and that a reaction intermediate is bound directly to the cluster. This active form has been trapped in a state, dubbed FeS(A), that was detected by electron paramagnetic resonance (EPR) spectroscopy when one-electron-reduced IspH was incubated

SUBMITTER: Xu W 

PROVIDER: S-EPMC3426640 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature