Sn-Glycerol-1-Phosphate Dehydrogenase in Methanobacterium thermoautotrophicum: Key Enzyme in Biosynthesis of the Enantiomeric Glycerophosphate Backbone of Ether Phospholipids of Archaebacteria

Abstract

One of the most characteristic features of archaebacterial ether phospholipids is the enantiomeric configuration of their glycerophosphate backbone (sn-glycerol-1-phosphate), that is the mirror image of the structure of the eubacterial or eukaryotic counterpart. The enzyme that forms glycerophosphate of this configuration was found for the first time in a cell-free extract of the methanogen, Methanobacterium thermoautotrophicum, and was identified as sn-glycerol-1-phosphate:NAD+ oxidoreductase (sn-glycerol-1-phosphate dehydrogenase) after partial purification. Because sn-glycerol-1-phosphate has been found to be a precursor of ether lipids of this organism, sn-glycerol-1-phosphate dehydrogenase is a key enzyme in the biosynthesis of the enantiomeric ether lipids of methanogens.