Evidence that oxidative dephosphorylation by the nonheme Fe( II), α-ketoglutarate: UMP oxygenase occurs by stereospecific hydroxylation.

LipL and Cpr19 are nonheme, mononuclear Fe( II)-dependent, α-ketoglutarate (α KG): UMP oxygenases that catalyze the formation of CO₂, succinate, phosphate, and uridine-5′-aldehyde, the last of which is a biosynthetic precursor for several nucleoside antibiotics that inhibit bacterial translocase I (MraY). To better understand the chemistry underlying this unusual oxidative dephosphorylation and establish a mechanistic framework for LipL and Cpr19, we report herein the synthesis of two biochemical probes-[1′,3′,4′,5′,5′-²H] UMP and the phosphonate derivative of UMP-and their activity with both enzymes. The results are consistent with a reaction coordinate that proceeds through the loss of one ²H atom of [1′,3′,4′,5′,5′-²H] UMP and stereospecific hydroxylation geminal to the phosphoester to form a cryptic intermediate, (5′ R)-5′-hydroxy- UMP. Thus, these enzyme catalysts can additionally be assigned as UMP hydroxylase-phospholyases. [ABSTRACT FROM AUTHOR]