Glycerol 1-phosphate

Biosynthesis and metabolism

Glycerol 1-phosphate is synthesized by reducing dihydroxyacetone phosphate (DHAP), 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. :[[File:Dihydroxyacetonphosphat Skelett.svg|x40px|DHAP]] + NAD(P)H + H+ → [[File:Glycerin-1-phosphat Skelett.svg|x40px|G1P]] + NAD(P)+

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.

Lipid divide

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.

It is known from genetic engineering that cells (specifically modified E. coli) 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.

Notes

References

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6. (2012). "Archaeal Phospholipid Biosynthetic Pathway Reconstructed in Escherichia coli". Archaea.
7. (1 January 2021). "Bridging the membrane lipid divide: bacteria of the FCB group superphylum have the potential to synthesize archaeal ether lipids". The ISME Journal.
8. (20 May 2025). "Permeability selection of biologically relevant membranes matches the stereochemistry of life on Earth". PLOS Biology.