Molecular characterization of two cya mutations, cya-854 and cyaR1

The cya-854 mutation of Escherichia coli K-12 (E. Brickman, L. Soll, and J. Beckwith, J. Bacteriol. 116:582-587, 1973) has been shown to consist of a 200-base-pair deletion generating a new translation start that permits synthesis of the adenylate cyclase carboxy terminus. Contrary to expectations (C. Guidi-Rontani, A. Danchin, and A. Ullmann, J. Bacteriol. 148:753-761, 1981), cyaR1 results from the insertion of an IS1 element into the sequence coding for the catalytic center of the protein.