title: Cyclopropane fatty acid synthase of Escherichia coli: deduced amino acid sequence, purification, and studies of the enzyme active site.
abstract: Cyclopropane fatty acid (CFA) synthase of Escherichia coli catalyzes a modification of the acyl chains of phospholipid bilayers. We report (i) identification of the CFA synthase protein, (ii) overproduction (> 600-fold) and purification to essential homogeneity of the enzyme, and (iii) the amino acid sequence of CFA synthase as deduced from the nucleotide sequence of the cfa gene. CFA synthase was overproduced by use of the T7 promoter/RNA polymerase system under closely defined conditions. The enzyme was readily purified by a two-step procedure requiring only ammonium sulfate fractionation and binding to phospholipid vesicles followed by flotation in sucrose density gradients. The deduced amino acid sequence predicts a protein of 43,913 Da (382 residues) that lacks long hydrophobic segments. The CFA synthase sequence has no significant similarity to known proteins except for sequences found in other enzymes that utilize S-adenosyl-L-methionine. We also report inhibitor studies of the enzyme active site.
authors.affiliation: Department of Microbiology, University of Illinois, Urbana 61801.
authors.forename: A Y
authors.initials: AY
authors.lastname: Wang
authors.forename: D W
authors.initials: DW
authors.lastname: Grogan
authors.forename: J E
authors.initials: JE
authors.lastname: Cronan
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002384:Catalysis; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D008780:Methyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014764:Viral Proteins
chemical_list: D014764:Viral Proteins; D008780:Methyltransferases; C019964:cyclopropane synthetase; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases