Evidence for repetitive structure of the large acyl-carrier protein subunit of Escherichia coli citrate lyase.

The amino acid composition of the unusually large acyl-carrier protein subunit of citrate lyase from Escherichia coli is characteristic of a protein with a highly repetitive structure. Peptide mapping studies provide further evidence of repetitive sequences within the subunit. Only a single Pauly-positive spot is detected in the tryptic peptide map although the subunit contains 8 histidine residues. The 4 prosthetic groups covalently bound to the subunit are recovered in a single tryptic fragment in almost quantitative yield. These structural features of the large acyl-carrier protein subunit probably reflect internal gene duplications.