This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: betaine lipid biosynthesis
|Superclasses:||Biosynthesis → Fatty Acids and Lipids Biosynthesis|
|Biosynthesis → Secondary Metabolites Biosynthesis|
Glycerolipids contain a diacylglycerol moiety to attached to a polar head group and is a common polar lipid found in biological membranes [Klug01]. Betaine lipids have a quaternary amine alcohol bound in ether linkage to the diacylglycerol moiety and are a class of glycerolipids [Klug01]. They are non-phosphorous glycerolipid analogs of a phosphatidylcholine [Riekhof05].
About this Pathway
The betaine lipid diacylglycerol-NNN-trimethylhomoserine (DGTS) and a closely related isoform diacylglycerol-O-2'-hydroxymethyl N,N,N,-trimethyl-β-alanine were discovered in the unicellular alga Ochromonas danica [Brown74]. The biosynthesis of these lipids has been studied in phosphate starved cells of the purple bacterium Rhodobacter sphaeroides [Klug01]. DGTS has also been found in the green alga Chlamydomonas reinhardtii and other lower plants and fungi, and may take the place of phosphatidylcholine in the membranes of these organisms. DGTS is a significant polar acyl lipid of the chloroplast thylakoid membrane and cellular fraction, in Chlamydomonas reinhardtii [Janero82]. While cellular DGTS contains a greater proportion of C-20 and equal amounts of saturated and tetraene fatty acids, the DGTS of the thylakoids is richer in trienes [Janero82].
Brown74: Brown AE, Elovson J (1974). "Isolation and characterization of a novel lipid, 1(3),2-diacylglyceryl-(3)-O-4'-(N,N,N-trimethyl)homoserine, from Ochromonas danica." Biochemistry 13(17);3476-82. PMID: 4367424
Janero82: Janero DR, Barrnett R (1982). "Isolation and characterization of an ether-linked homoserine lipid from the thylakoid membrane of Chlamydomonas reinhardtii 137+." J Lipid Res 23(2);307-16. PMID: 7077145
Klug01: Klug RM, Benning C (2001). "Two enzymes of diacylglyceryl-O-4'-(N,N,N,-trimethyl)homoserine biosynthesis are encoded by btaA and btaB in the purple bacterium Rhodobacter sphaeroides." Proc Natl Acad Sci U S A 98(10);5910-5. PMID: 11331765
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