The cyclic-2,3-diphosphoglycerate fromMethanobacterium thermoautotrophicum is thed enantiomer

The cyclic pyrophosphate obtained fromMethanobacterium thermoautotrophicum was converted tosn-glycerol 3-phosphate by a stereospecific route. This conversion establishes the structure as cyclic-2,3-diphospho-d-glycerate. The same method was used to determine the cellular content of this metabolite under two conditions: batch culture in a medium containing 2 mM inorganic phosphate and continuous culture with 0.1 mM phosphate in the inflowing medium. The values found were 194±13 and 27.5±1.1 mol/g dry weight, respectively. Computer modeling indicated that the pyrophosphate group cannot adopt a staggered conformation.