sn -Glycerol-1-Phosphate-Forming Activities in Archaea : Separation of Archaeal Phospholipid Biosynthesis and Glycerol Catabolism by Glycerophosphate Enantiomers

Abstract

In Methanobacterium thermoautotrophicum,sn-glycerol-1-phosphate (G-1-P) dehydrogenase is responsible for the formation of the Archaea-specific backbone of phospholipids, G-1-P, from dihydroxyacetonephosphate (DHAP). The possible G-1-P-forming activities were surveyed in cell-free extracts of six species of Archaea. All the archaeal cell-free homogenates tested revealed the ability to form G-1-P from DHAP. In addition, activities of G-3-P-forming glycerol kinase and G-3-P dehydrogenase were also detected in four heterotrophic archaea, while glycerol kinase activity was not detected in two autotrophic methanogens. These results show that G-1-P is produced from DHAP by G-1-P dehydrogenase in a wide variety of archaea while exogenous glycerol is catabolized via G-3-P.

Resolving the origins of membrane phospholipid biosynthesis genes using outgroupfree rooting

“…In contrast to our analyses of proteins of the classical archaeal pathway, phylogenies of proteins of bacterial-type membrane phospholipid biosynthesis pathways suggested that their orthologues in Archaea were the result of relatively recent horizontal acquisitions. Homologues of both forms of G3PDH and GlpK are broadly distributed in Archaea, however these three enzymes are not exclusive to phospholipid synthesis, and have been shown to be used in glycerol metabolism in some autotrophic Archaea (Nishihara et al 1999). Of the enzymes thought to function exclusively in bacterial membrane phospholipid biosynthesis, we did not find any archaeal homologues for PlsB or PlsX.…”

Glycerol metabolism of haloarchaea

“…A gene for G1P dehydrogenase was identified in all the haloarchaeal genomes surveyed. G1P dehydrogenase is an essential enzyme in archaea because it generates the glycerophosphate backbone (G1P) of archaeal diether phospholipids (Nishihara et al ., ). Whereas bacteria and eucaryotes contain d ‐glycerol in their cell membranes, archaea possess l ‐glycerol in their cell membranes, and the G1P of archaeal phospholipids is linked to isoprenyl side chains using highly stable ether bonds (White et al ., ).…”

Glycerol metabolism in hypersaline environments

“…The plasmid‐encoded glycerol dehydrogenase of Halobacterium salinarum has been characterized and structurally elucidated. The produced dihydroxyacetone might be phosphorylated by an ATP‐ or phosphoenolpyruvate:phosphotransferase system‐dependent dihydroxyacetone kinase and fed into the lower Embden–Meyerhof pathway or converted to other metabolic intermediates including sn‐glycerol‐1‐phosphate, the backbone of archaeal phospholipids (Rawal et al ., ; Nishihara et al ., ; Falb et al ., ; Sherwood et al ., ).…”