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Publication Abstract from PubMed

Many microorganisms use flavin-dependent thymidylate synthase (FDTS) to synthesize the essential nucleotide 2'-deoxythymidine 5'-monophosphate (dTMP) from 2'-deoxyuridine 5'-monophosphate (dUMP), 5,10-methylenetetrahydrofolate (CH2THF), and NADPH. FDTSs have a structure that is unrelated to the thymidylate synthase used by humans and a very different mechanism. Here we report nuclear magnetic resonance evidence that FDTS ionizes N3 of dUMP using an active-site arginine. The ionized form of dUMP is largely responsible for the changes in the flavin absorbance spectrum of FDTS upon dUMP binding. dUMP analogues also suggest that the phosphate of dUMP acts as the base that removes the proton from C5 of the dUMP-methylene intermediate in the FDTS-catalyzed reaction. These findings establish additional differences between the mechanisms of FDTS and human thymidylate synthase.

Deprotonations in the Reaction of Flavin-Dependent Thymidylate Synthase.,Stull FW, Bernard SM, Sapra A, Smith JL, Zuiderweg ER, Palfey BA Biochemistry. 2016 Jun 14;55(23):3261-9. doi: 10.1021/acs.biochem.6b00510. Epub, 2016 Jun 2. PMID:27214228^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.