- Methylphosphonic Acid Biosynthesis and Catabolism in Pelagic Archaea and Bacteria
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Inorganic phosphate is essential for all life forms, yet microbes in marine environments are in near constant deprivation of this important nutrient. Organophosphonic acids can serve as an alternative source of inorganic phosphate if microbes possess the appropriate biochemical pathways that allow cleavage of the stable carbon–phosphorus bond that defines this class of molecule. One prominent source of inorganic phosphate is methylphosphonic acid, which is found as a constituent of marine-dissolved organic matter. The cycle of biosynthesis and catabolism of methylphosphonic acid by marine microbes is the likely source of supersaturating levels of methane in shallow ocean waters. This review provides an overview of the rich biochemistry that has evolved to synthesize methylphosphonic acid and catabolize this molecule into Pi and methane, with an emphasis on the reactions catalyzed by methylphosphonic acid synthase MpnS and the carbon–phosphorus lyase system. The protocols and experiments that are described for MpnS and carbon–phosphorus lyase provide a foundation for studying the structures and mechanisms of these and related enzymes.
- Ulrich, Emily C.,Kamat, Siddhesh S.,Hove-Jensen, Bjarne,Zechel, David L.
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p. 351 - 426
(2018/05/16)
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- Prebiotic synthesis of aminooxazoline-5′-phosphates in water by oxidative phosphorylation
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RNA is essential to all life on Earth and is the leading candidate for the first biopolymer of life. Aminooxazolines have recently emerged as key prebiotic ribonucleotide precursors, and here we develop a novel strategy for aminooxazoline-5′-phosphate synthesis in water from prebiotic feedstocks. Oxidation of acrolein delivers glycidaldehyde (90%), which directs a regioselective phosphorylation in water and specifically affords 5′-phosphorylated nucleotide precursors in upto 36% yield. We also demonstrated a generational link between proteinogenic amino acids (Met, Glu, Gln) and nucleotide synthesis.
- Fernández-García,Grefenstette,Powner
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supporting information
p. 4919 - 4921
(2017/07/11)
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- FURANOSE RING ANOMERIZATION: A KINETIC STUDY OF THE 5-DEOXYPENTOSES AND 5-O-METHYLPENTOSES
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The anomerzation of 5-deoxy-L-pentoses (1-4) and 5-O-methyl-D-pentoses (5-8) in aqueous solution has been studied by (13)C saturation-transfer n.m.r. (s.t.-n.m.r.) spectroscopy, using compounds substituted with (13)C at the anomeric carbon atom.Unidirectional rate-constants of ring-opening (kopen) and ring closing (kclose) have been obtained for these compounds under identical solution conditions (50mM acetate buffer, pH 4.0 at 60 deg C), and have been compared to those measured for the D-tetroses (9 and 10) and four D-pentose 5-phosphates (11-14).Based on these comparisons, several correlations between furanose structure and reactivity have been revealed, and models have been proposed to explain the observed kinetic behavior of compounds 1-10.The effect of exocyclic structure on acid-catalyzed rate-constants was also examined by comparing the behavior of 5-deoxy-L-lyxose and 5-O-methyl-D-lyxose.Some consideration has been given to identifying the factors (enthalpic and entropic) that may play roles in determining the effect of structure on anomerization reactivity.
- Snyder, Joseph R.,Serianni, Anthony S.
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- Anomerization of Furanose Sugars and Sugar Phosphates
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Thermodynamic and kinetic parameters for the ring-opening and -closing reactions of several aldo- and ketofuanoses and their phosphate esters have been determined by NMR line-width and saturation-transfer methods.Cyclic forms interconvert via a single, acyclic carbonyl form under either acid or base catalysis.Ring-opening rates do not correlate with thermodynamic stability of the rings.For aldofuranose phosphates, α anomers open faster than β anomers; for ketofuranose phosphates the converse is observed.Intramolecular catalysis of anomerization by the phosphate group of sugar phosphates is documented.Biological and mechanistic implications of the observed kinetics are discussed.
- Pierce, John,Serianni, Anthony S.,Barker, Robert
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p. 2448 - 2456
(2007/10/02)
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