''sn''-Glycerol 1-phosphate is the conjugate base of a

phosphoric ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distincti ...

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

. It is a component of

ether lipid In biochemistry, an ether lipid refers to any lipid in which the lipid "tail" group is attached to the glycerol backbone via an ether, ether bond at any position. In contrast, conventional glycerophospholipids and triglycerides are triesters. St ...

s, which are common for

archaea Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even thou ...

Biosynthesis and metabolism

Glycerol 1-phosphate is synthesized by reducing

dihydroxyacetone phosphate Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCH2C(O)CH2OPO32-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis.Nelson, D. L.; Co ...

(DHAP), a

glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvic acid, pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The Thermodynamic free energy, free energy released in this process is used to form ...

intermediate, with ''sn''-glycerol-1-phosphate dehydrogenase. DHAP and thus glycerol 1-phosphate is also possible to be synthesized from

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the Proteinogenic amino acid, 22 α-amino acids incorporated into p ...

and

citric acid cycle The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle)—is a series of chemical reaction, biochemical reactions that release the energy stored in nutrients through acetyl-Co ...

intermediates via

gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the biosynthesis of glucose from certain non-carbohydrate carbon substrates. It is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In verte ...

pathway. : Dihydroxyacetonphosphat Skelett

+ NAD(P)H + H⁺ → Glycerin-1-phosphat Skelett

+ NAD(P)⁺ Glycerol 1-phosphate is a starting material for ''de novo'' synthesis of ether lipids, such as those derived from

archaeol Archaeol is a diether composed of two phytanyl chains linked to the sn-2 and sn-3 positions of glycerol. As its phosphate ester, it is a common component of the membranes of archaea. Structure and contrast with other lipids The 2,3-sn-glycerol ...

and

caldarchaeol Caldarchaeol is a membrane-spanning lipid of the Terpenoid, isoprenoid glycerol dialkyl glycerol tetraether (Glycerol dialkyl glycerol tetraether, iGDGT) class, produced and used by archaea. Membranes made up of caldarchaeol are more stable since ...

. 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 Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

and

eukaryote The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

s, use the

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

glycerol 3-phosphate ''sn''-Glycerol 3-phosphate is the organic ion with the formula HOCH2CH(OH)CH2OPO32-. It is one of two stereoisomers of the ester of dibasic phosphoric acid (HOPO32-) and glycerol. It is a component of bacterial and eukaryotic glycerophospholi ...

for producing their cell membranes. The fact that archaea use the flipped chirality compared to these two groups is termed a lipid divide. (The other part of the lipid divide is that archaea use

s while bacteria and eukarya use ester lipids, though this has turned out to be a lot less strict than the chirality divide.) , biologists still do not know how the lipid divide happened. 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 The last universal common ancestor (LUCA) is the hypothesized common ancestral cell from which the three domains of life, the Bacteria, the Archaea, and the Eukarya originated. The cell had a lipid bilayer; it possessed the genetic code a ...

, 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

{{reflist Organophosphates Phosphate esters Glycerol esters

Biosynthesis and metabolism

Lipid divide

See also

Notes