- Transition State Structure and Inhibition of Rv0091, a 5′-Deoxyadenosine/5′-methylthioadenosine Nucleosidase from Mycobacterium tuberculosis
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5′-Methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) is a bacterial enzyme that catalyzes the hydrolysis of the N-ribosidic bond in 5′-methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH). MTAN activity has been linked to quorum sensing pathways, polyamine biosynthesis, and adenine salvage. Previously, the coding sequence of Rv0091 was annotated as a putative MTAN in Mycobacterium tuberculosis. Rv0091 was expressed in Escherichia coli, purified to homogeneity, and shown to be a homodimer, consistent with MTANs from other microorganisms. Substrate specificity for Rv0091 gave a preference for 5′-deoxyadenosine relative to MTA or SAH. Intrinsic kinetic isotope effects (KIEs) for the hydrolysis of [1′-3H], [1′-14C], [5′-3H2], [9-15N], and [7-15N]MTA were determined to be 1.207, 1.038, 0.998, 1.021, and 0.998, respectively. A model for the transition state structure of Rv0091 was determined by matching KIE values predicted via quantum chemical calculations to the intrinsic KIEs. The transition state shows a substantial loss of C1′-N9 bond order, well-developed oxocarbenium character of the ribosyl ring, and weak participation of the water nucleophile. Electrostatic potential surface maps for the Rv0091 transition state structure show similarity to DADMe-immucillin transition state analogues. DADMe-immucillin transition state analogues showed strong inhibition of Rv0091, with the most potent inhibitor (5′-hexylthio-DADMe-immucillinA) displaying a Ki value of 87 pM.
- Namanja-Magliano, Hilda A.,Stratton, Christopher F.,Schramm, Vern L.
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- SYNTHESIS AND N.M.R.-SPECTRAL ANALYSIS OF UNENRICHED AND -ENRICHED 5-DEOXYPENTOSES AND 5-O-METHYLPENTOSES
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Chemical methods are described for preparing unenriched and -enriched 5-deoxy- and 5-O-methyl-pentoses in the D or L configuration.The 1H-n.m.r.-spectra of these compounds have been interpreted, and the 13C n.m.r. spectra assigned with the aid of 2-D 13C-1H chemical-shift correlation spectroscopy.Tautomeric forms (furanoses, hydrate, and aldehyde) in solution in 2H2O have been quantified with the aid of -enriched derivatives.Spectra of 5-deoxypentoses, and methyl pentofuranosides have been compared, in order to assess the effect of 5-C-deoxygenation and 5-O-methylation on chemical shifts and coupling constants (1H-1H, 13C-1H, and 13C-13C) and on the pentofuranose conformations.
- Snyder. Joseph R.,Serianni, Anthony S.
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p. 169 - 188
(2007/10/02)
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- 5'-Deoxy-5-fluorouridine
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A process for the manufacture of 5'-deoxy-5-fluorouridine which is a potent antitumor agent. The process comprises cleaving the acyl groups from a 1-(5-deoxy-2,3-di-O-acyl-β-D-ribofuranosyl)-5-fluorouracil, a novel intermediate in the process.
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