A Missense Mutation Accounts for the Defect in the Glycerol-3-Phosphate Acyltransferase Expressed in the plsB26 Mutant

The sn-glycerol-3-phosphate acyltransferase (plsB) catalyzes the first step in membrane phospholipid formation. A conditional Escherichia coli mutant (plsB26) has a single missense mutation (G1045A) predicting the expression of an acyltransferase with an Ala349Thr substitution. The PlsB26 protein had a significantly reduced glycerol-3-phosphate acyltransferase specific activity coupled with an elevated K(m) for glycerol-3-phosphate.