ARABIDOPSIS
ACYL-LIPID METABOLISM
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Legend: The pool of diacylglycerol (DAG) backbones for the so called prokaryotic lipid synthesis is generated exclusively/entirely inside the plastid: Dihydroxyacetonephosphate (DHAP) is reduced to glycerol 3-phosphate (G3P) which is then first acylated at the sn-1 position with an activated fatty acid (18:1 ACP) by glycerol-3-phosphate acyltransferase (GPAT) to lysophosphatidic acid (LPA). LPA in turn is then acylated at the sn-2 position with 16:0 by the lysophosphatidic acid acyltransferase (LPAAT) to phosphatidic acid (PA). The specificity of this particular acyltransferase for C16 fatty acids distinguishes the prokaryotic from the eukaryotic lipids. PA is either dephosphorylated by PA phosphatase (PP) to DAG which serves as precursor for galactolipid and sulfolipid biosynthesis (see diagram B), or a CDP-DAG synthase (CDP-DAGS) uses PA to synthesize activated CDP-DAG, which - together with G3P - is required for phosphatidylglycerol phosphate (PGP) synthesis, the precursor of phosphatidylglycerol (PG).
Prokaryotic Galactolipid, Sulfolipid, & Phospholipid Synthesis 1
PG&S
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