beta-Ketoacyl-ACP synthase I of Escherichia coli: nucleotide sequence of the fabB gene and identification of the cerulenin binding residue.

The fabB gene of E. coli encoding beta-ketoacyl-ACP synthase I has been isolated by complementation and sequenced. The enzyme has been purified and its NH2-terminal residues sequenced. Identification of the active site was accomplished by tagging with 3H-cerulenin and radio sequencing of the region. Comparison of the deduced primary structures of the fabB gene product with the FAS2 gene product of Saccharomyces cerevisiae revealed the probable active site in chalcone synthases of higher plants.