FIG. 4.

Sequence of S-R intergenic region. The sequence of the S-R intergenic region is shown, with the corresponding C-terminal sequences of S and N-terminal sequences of R. Also shown are the sequences of the D103am and E102am mutants. In each case, the presumptive Shine-Dalgarno sequence for R is underlined and both the wild-type start codon and the first downstream alternative start codon for R are shown in boldface. Asterisks denote the sequence alterations resulting from the creation of the corresponding amber codons in the S reading frame.