β-ketoacyl-ACP synthase I of Escherichia coli: Nucleotide sequence of thefabB gene and identification of the cerulenin binding residue

Abstract
ThefabB gene of E. coli encoding β-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 with3H-cerulenin and radio sequencing of the region. Comparison of the deduced primary structures of thefabB gene product with theFAS2 gene product of Saccharomyces cerevisiae revealed the probable active site in chalcone synthases of higher plants.