From carbon precursors to membrane lipids

Fatty-acid production

Acetyl-CoA → malonyl-CoA → acyl-ACP

ACC, FabD and FabH start the chain. FabG, a dehydratase and an enoyl reductase process it; FabB/FabF elongate it with additional malonyl-ACP.

Phosphatidic-acid formation

Glycerol-3-phosphate → LPA → PA

A first acylation uses PlsB or the alternative PlsX/PlsY route. PlsC attaches a second chain. These choices vary among bacteria.

Phospholipid headgroups

PA → CDP-DAG → PG or PE

CdsA produces CDP-DAG. The PG branch uses PgsA and a phosphatase; the PE branch uses PssA and Psd in the illustrated E. coli example.

Evidence and scope

Original explanatory diagram based on the sources below. These are selected documented biochemical routes or mechanisms, not a complete species-specific reconstruction. Each arrow can summarize several reactions; panels may represent branches or alternatives. Genome annotations, protein models and organism-specific evidence remain in the detailed system map.

• Reconstituted E. coli fatty-acid synthesis
• Reconstituted bacterial phospholipid synthesis
• Experimental PlsX/PlsY initiation pathway