611-55-2Relevant articles and documents
Identification of a cyclic nucleotide as a cryptic intermediate in molybdenum cofactor biosynthesis
Hover, Bradley M.,Loksztejn, Anna,Ribeiro, Anthony A.,Yokoyama, Kenichi
, p. 7019 - 7032 (2013/06/05)
The molybdenum cofactor (Moco) is a redox cofactor found in all kingdoms of life, and its biosynthesis is essential for survival of many organisms, including humans. The first step of Moco biosynthesis is a unique transformation of guanosine 5′-triphosphate (GTP) into cyclic pyranopterin monophosphate (cPMP). In bacteria, MoaA and MoaC catalyze this transformation, although the specific functions of these enzymes were not fully understood. Here, we report the first isolation and structural characterization of a product of MoaA. This molecule was isolated under anaerobic conditions from a solution of MoaA incubated with GTP, S-adenosyl-l-methionine, and sodium dithionite in the absence of MoaC. Structural characterization by chemical derivatization, MS, and NMR spectroscopy suggested the structure of this molecule to be (8S)-3′,8-cyclo-7,8-dihydroguanosine 5′-triphosphate (3′,8-cH2GTP). The isolated 3′,8-cH2GTP was converted to cPMP by MoaC or its human homologue, MOCS1B, with high specificities (Km 2GTP. These observations, in combination with some mechanistic studies of MoaA, unambiguously demonstrate that MoaA catalyzes a unique radical C-C bond formation reaction and that, in contrast to previous proposals, MoaC plays a major role in the complex rearrangement to generate the pyranopterin ring.
Stability of 7,8-dihydropterins in air-equilibrated aqueous solutions
Dantola, M. Laura,Vignoni, Mariana,Capparelli, Alberto L.,Lorente, Carolina,Thomas, Andres H.
body text, p. 411 - 425 (2009/02/07)
6-Substituted 7,8-dihydropterins (=2-amino-7,8-dihydropteridin-4(1H)-ones) are heterocyclic compounds that occur in a wide range of living systems and participate in relevant biological functions. In airequilibrated aqueous solutions, these compounds react with dissolved O2 (autooxidation). The rates of these reactions as well as the products formed strongly depend on the chemical structure of the substituents. 7,8-Dihydro-6-methylpterin and 7,8-dihydro-6,7-dimethylpterin that bear electron-donor groups as substituents are the most reactive derivatives and undergo oxidation of the pterin moiety to yield the corresponding oxidized derivatives (6-methylpterin and 6,7-dimethylpterin, resp.). The oxidations of 7,8-dihydrobiopterin, 7,8-dihydroneopterin, and 7,8-dihydrofolic acid are slower, and they yield 7,8-dihydroxanthopterin as the main product. 7,8-Dihydroxanthopterin, 6-formyl-7,8-dihydropterin, and sepiapterin are rather stable, and their consumption in air-equilibrated solutions is negligible for several days. The pseudo-first-order rate constants of the reactions between these compounds and O2 at 25° and 40° are reported. The biological implications of the results obtained are also discussed.
A prototype solid phase synthesis of pteridines and related heterocyclic compounds
Gibson, Colin L.,La Rosa, Salvatore,Suckling, Colin J.
, p. 1909 - 1918 (2007/10/03)
The development of a versatile solid phase synthesis of bicyclic polyaza heterocycles including pteridines, purines, and deazapurines is described. The strategy comprises the linking of a pre-formed pyrimidine through a thioether at the 2 or 4 position to a polystyrene resin, the cyclisation of the second ring, and the direct or oxidative cleavage of the product from the resin by nucleophilic substitution. This provides not only for substituent variation in the second ring, but also for variation at the site of cleavage. Limitations in the scope of the methodology are set by the intrinsic reactivity of pyrimidinyl 2- or 4-thioethers which, whilst undergoing ready nitration at C5, are surprisingly difficult to alkylate and acylate.
