Elucidation of the structure of methanopterin, a coenzyme from Methanobacterium thermoautotrophicum, using two‐dimensional nuclear‐magnetic‐resonance techniques

Abstract

Methanopterin is a coenzyme involved in methanogenesis. From 2 kg wet cells of Methanobacterium thermoautotrophicum about 35 μmol methanopterin were isolated. The structure of this compound was elucidated by various two‐dimensional nuclear‐magnetic‐resonance techniques. Methanopterin was identified as N‐[1′‐(2″‐amino‐4″‐hydroxy‐7″‐ methyl‐6″‐ pteridinyl)ethyl]‐4‐[2′,3′,4′,5′‐ tetrahydroxypent‐1′‐ yl (5′→1″) O‐α‐ribofuranosyl‐5″‐phosphoric acid] aniline, in which the phosphate group is esterified with α‐hydroxyglutaric acid. The molecular formula of the sodium salt of methanopterin at pH 7.0 is C30H38O16N6PNa3·xH2O (x is about 4). The anhydrous sodium salt of methanopterin has a molecular mass of 838.60 Da and the molar absorption coefficient at 342 nm is 7.4 mM−1 cm−1 at pH 7.0. Copyright © 1984, Wiley Blackwell. All rights reserved