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We report the cloning and nucleotide sequence of the gene encoding malonyl coenzyme A‐acyl carrier protein transacylase of Escherichia coli, Malonyl transacylase has been overexpressed 155‐fold compared to a wild‐type strain, Overexpression of this enzyme alters the fatty acid composition of a wild‐type E. coli strain; increased amounts of cis‐vaccenate are incorporated into the membrane phospholipids.

The glp operons of Escherichia coli are negatively controlled by the glp repressor. Comparison of the repressor-binding affinities for consensus and altered consensus operators in vivo showed that all base substitutions at positions 3, 4, 5, and 8 from the center of the palindromic operator caused a striking decrease in repressor binding. Substitutions at other positions had a severe to no The proteins that catalyze the steps required for the utilization of glycerol, glycerol-3-phosphate (glycerol-P), and glycerophosphodiesters are encoded by the glp regulon of Escherichia coli (14). The glp regulon is composed of five operons located at three different regions on the linkage map of E. coli. Transcription of the glp operons is negatively regulated by the glp repressor, a tetrameric protein encoded by the glpR gene (13,17). Negative control is mediated by binding of the glp repressor to its operator sites within the glp operons. The affinity of the repressor for its operators is decreased in the presence of glycerol-P, the inducer for the regulon (14). Thirteen operators have been identified in the glp operons by using DNase I footprinting (12,22,23). The operators match more or less well the consensus operator 5'-WATGTTCGWT AWCGAACA TW-3' (W is A or T, and the dot indicates the center of symmetry) (22). Tandemly repeated repressor-binding sites are present in the control regions of the glpA CB, glpD, and glpFKX operons (12,20,22,23 Cloning of operator DNA. Plasmid vector pGEM3Z (Promega) was digested with BamHI and Pstl and purified following electrophoresis on low-gelling-temperature agarose. Equimolar amounts of the oligonucleotides to be cloned were mixed in 10 mM Tris-HCl (pH 8)-50 mM NaCl-1 mM EDTA and heated to 85°C. The annealing mixture was allowed to cool to room temperature for several hours. A 40-fold molar excess of annealed oligonucleotides was mixed and ligated (3 h) to 150 ng of cleaved vector DNA in 0.04 ml. An aliquot of the ligation mixture was used for transformation of strain DH5otF'.

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