Methanophosphagen: Unique cyclic pyrophosphate isolated from Methanobacterium thermoautotrophicum
Abstract
A unique cyclic pyrophosphate compound has been detected at 10-12 mM intracellular concentration in Methanobacterium thermoautotrophicum by in vivo 31P NMR. This compound has been extracted from cells and purified by anion-exchange chromatography. Studies with 1H, 13C, and 31P NMR and fast-atom-bombardment mass spectrometry have identified it as 2,3-cyclopyrophosphoglycerate, an intramolecularly cyclized pyrophosphate of 2,3-diphosphoglycerate. Chemical degradation to 2,3-diphosphoglycerate and synthesis by dicyclohexylcarbodiimide coupling of 2,3-diphosphoglycerate are consistent with this identification. It is suggested that this compound serves as a primary phosphagen in methanogens.
