Glycerol 1-phosphate

sn-Glycerol 1-phosphate is the conjugate base of a phosphoric ester of glycerol. It is a component of ether lipids, which are common for archaea.

Biosynthesis and metabolism

Glycerol 1-phosphate is synthesized by reducing dihydroxyacetone phosphate, a glycolysis intermediate, with sn-glycerol-1-phosphate dehydrogenase. DHAP and thus glycerol 1-phosphate is also possible to be synthesized from amino acids and citric acid cycle intermediates via gluconeogenesis pathway.
Glycerol 1-phosphate is a starting material for de novo synthesis of ether lipids, such as those derived from archaeol and caldarchaeol. It is first geranylgeranylated on its sn-3 position by a cytosolic enzyme, phosphoglycerol geranylgeranyltransferase. A second geranylgeranyl group is then added on the sn-2 position making unsaturated archaetidic acid.

Organisms other than archaea, i.e. bacteria and eukaryotes, use the enantiomer glycerol 3-phosphate for producing their cell membranes. The fact that archaea use the flipped chirality compared to these two groups is termed a lipid divide. , biologists still do not know how the lipid divide happened.
It is known from genetic engineering that cells that produce both types of lipids at the same time are viable. Genetic evidence for a natural mixed-membrane system have also been found, pending definitive proof by chemical analysis. This lends to the idea that the common ancestor of bacteria and archaea, especially the last universal common ancestor, may have had a mixed membrane. Assuming this is the case, this still leaves open the question of why most current life forms only use one of these chiralities. One hypothesis involves the permeability of mixed and non-mixed membranes to common building blocks of life.