title: Altered molecular form of acyl carrier protein associated with beta-ketoacyl-acyl carrier protein synthase II (fabF) mutants.
abstract: Acyl carrier protein (ACP) is a required cofactor for fatty acid synthesis in Escherichia coli. Mutants lacking beta-ketoacyl-ACP synthase II activity (fabF1 or fabF3) possessed a different molecular species of ACP (F-ACP) that was separated from the normal form of the protein by conformationally sensitive gel electrophoresis. Synthase I mutants contained the normal protein. Complementation of fabF1 mutants with an F' factor harboring the wild-type synthase II allele resulted in the appearance of normal ACP, whereas complementation with an F' possessing the fabF2 allele (a mutation that produces a synthase II enzyme with altered catalytic activity) resulted in the production of both forms of ACP. The structural difference between F-ACP and ACP persisted after the removal of the 4'-phosphopantetheine prosthetic group, and both forms of the protein had identical properties in an in vitro fatty acid synthase assay. Both ACP and F-ACP were purified to homogeneity, and their primary amino acid sequences were determined. The two ACP species were identical but differed from the sequence reported for E. coli E-15 ACP in that an Asn instead of an Asp was at position 24 and an Ile instead of a Val was at position 43. Therefore, F-ACP appears to be a modification of ACP that is detected when beta-ketoacyl-ACP synthase II activity is impaired.
mesh_terms: D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000235:genetics* / Q000378:metabolism; D000213:Acyl Carrier Protein / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics*; D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000032:analysis* / Q000201:enzymology / Q000235:genetics; D005227:Fatty Acids / Q000096:biosynthesis; D005816:Genetic Complementation Test; D009154:Mutation; D009829:Oleic Acids / Q000096:biosynthesis
chemical_list: D000213:Acyl Carrier Protein; D005227:Fatty Acids; D009829:Oleic Acids; C065593:cis-vaccenic acid; D000217:Acyltransferases; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase