FIG 4.
The spontaneous mutations increased expression of the FabK ENR. (A) ENR activities of the wild-type FA2-2, spontaneous mutants, and the complementing plasmid-bearing strains. The 100-μl ENR reaction mixtures contained 0.1 M sodium phosphate buffer (pH 7.0), 0.15 mM NADH, and 2 μg of cell extract protein, and NADH-dependent ENR activity was assayed. The reactions were initiated by addition of 100 μM trans-2-decenoyl-ACP. The data are from three independent experiments and are expressed as means ± standard deviations. (B) Incorporation of [1-14C]acetate into the membrane phospholipids of the wild-type strain FA2-2, the spontaneous mutant strains, and the ΔfabI strain FAZL1 transformed with the wild-type fabK gene or the mutant alleles. The strains used here are the same with those in Fig. 2. The fatty acid methyl esters were prepared and analyzed by argentation thin-layer chromatography as described in Materials and Methods. Designations: Sat, saturated fatty acids; Δ9C16:1, palmitoleic (cis-9-hexadecenoic) acid; Δ11C18:1, cis-vaccenic (cis-11-octadecenoic) acid.