FIG 1.
Vancomycin-resistant lptD suppressors map to cdsA, the gene responsible for the conversion of phosphatidic acid to CDP-diacylglycerol. (A) The inner membrane CdsA protein is predicted to have seven transmembrane domains (33). Vancomycin-resistant cdsA suppressors mapped mainly within these domains. Mutations V16G, L33P, Δ56–62, Y156D, and L236Q were isolated in an lptDV52E-I54E background. I203S was isolated in an lptDI54E background, and R263L was isolated in an lptDΔD57ΔK60 background. The mutations enclosed in circles, I203S (cdsA7) and R263L (cdsA9), are characterized further in this study. (B) Biosynthetic pathway for major phospholipids in Escherichia coli. Protein names are in boxes, and they are next to the arrow that signifies the step at which they act.