Structural characterization of tatiopterin, a novel pterin isolated from Methanogenium tationis

Cofactor extracts of Methanogenium tationis were screened for the presence of pterin-derivatives. Methanopterin, sarcinapterin and 7-methylpterin were absent, while 2-amino-4-hydroxy-pteridine and another blue fluorescent compound with a pterin spectrum were detected. The latter pterin was purified by ion exchange and reversed-phase column chromatography. The structure of this compound was elucidated by combining spectrophotometry, amino acid analysis and 1H-NMR spectroscopy. The pterin, which we named tatiopterin, was identified as an aspartyl derivative of sarcinapterin with a 7-proton instead of a 7-methyl group in the pterin moiety. The IUPAC name is: N--1'-(2'-amino-4'-hydroxy-7'-proton-6'-pteridinyl)ethyl]-4- 2',3',4',5'-tetrahydroxypent-1'-yl(5'----1')O-alpha- ribofuranosyl-5'-phosphoric acid]aniline, in which the phosphate group is esterified with alpha-hydroxyglutarylglutamylaspartic acid.