Thiamin is an essential component of the human diet and is added to many commercial foods (RDA = 1.4 mg). Deficiency in this vitamin results in a neurological disease called beri-beri. At the molecular level, thiamin dependent enzymes play a particularly important role in carbohydrate metabolism and include transketolases, alpha-ketoacid decarboxylases, alpha-ketoacid oxidases, acetolactate synthase and glyoxalate synthase. The long range goals of our research are to understand the mechanistic enzymology and regulation of the thiamin biosynthetic pathway in Escherichia coli. These studies are significant for three reasons. Firstly, since this vitamin is a required component of the human diet, it is important to understand how it is biosynthesized. Secondly, from the perspective of basic science, the biosynthetic pathway involves an unusually large amount of novel mechanistic chemistry. Lastly, our studies will facilitate the construction of overexpression strains that may be of use for the commercial production of thiamin or its components (2,000 tons/year produced by total synthesis). In this grant, we will carry out a complete mechanistic characterization of the enzyme involved in the coupling of the thiazole and the pyrimidine moieties of thiamin (thiamin phosphate pyrophosphorylase). In parallel, we will carry out a series of experiments designed to identify the reactions involved in the thiazole biosynthesis. Once we have identified specific reactions, we will initiate systematic mechanistic studies on each enzyme.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Bio-Organic and Natural Products Chemistry Study Section (BNP)
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Cornell University
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Bhandari, Dhananjay M; Fedoseyenko, Dmytro; Begley, Tadhg P (2018) Mechanistic Studies on Tryptophan Lyase (NosL): Identification of Cyanide as a Reaction Product. J Am Chem Soc 140:542-545
Adak, Sanjoy; Begley, Tadhg P (2017) Flavin-N5-oxide: A new, catalytic motif in flavoenzymology. Arch Biochem Biophys 632:4-10
Wang, Yuanyou; Schnell, Bastien; Baumann, Sascha et al. (2017) Biosynthesis of Branched Alkoxy Groups: Iterative Methyl Group Alkylation by a Cobalamin-Dependent Radical SAM Enzyme. J Am Chem Soc 139:1742-1745
Adak, Sanjoy; Begley, Tadhg P (2017) RutA-Catalyzed Oxidative Cleavage of the Uracil Amide Involves Formation of a Flavin-N5-oxide. Biochemistry 56:3708-3709
Rodrigues, Matthew J; Windeisen, Volker; Zhang, Yang et al. (2017) Lysine relay mechanism coordinates intermediate transfer in vitamin B6 biosynthesis. Nat Chem Biol 13:290-294
Adak, Sanjoy; Begley, Tadhg P (2016) Dibenzothiophene Catabolism Proceeds via a Flavin-N5-oxide Intermediate. J Am Chem Soc 138:6424-6
Eser, Bekir E; Zhang, Xuan; Chanani, Prem K et al. (2016) From Suicide Enzyme to Catalyst: The Iron-Dependent Sulfide Transfer in Methanococcus jannaschii Thiamin Thiazole Biosynthesis. J Am Chem Soc 138:3639-42
Xu, Hui; Chakrabarty, Yindrila; Philmus, Benjamin et al. (2016) Identification of the First Riboflavin Catabolic Gene Cluster Isolated from Microbacterium maritypicum G10. J Biol Chem 291:23506-23515
Nemeria, Natalia S; Shome, Brateen; DeColli, Alicia A et al. (2016) Competence of Thiamin Diphosphate-Dependent Enzymes with 2'-Methoxythiamin Diphosphate Derived from Bacimethrin, a Naturally Occurring Thiamin Anti-vitamin. Biochemistry 55:1135-48
Jhulki, Isita; Chanani, Prem K; Abdelwahed, Sameh H et al. (2016) A Remarkable Oxidative Cascade That Replaces the Riboflavin C8 Methyl with an Amino Group during Roseoflavin Biosynthesis. J Am Chem Soc 138:8324-7

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