Fig. 8. Comparative sequence analysis of cdd genes from B.subtilis (upper sequence) and B.firmus (lower sequence). FS site, position of frameshifting site in cdd gene from B.subtilis; SD, Shine–Dalgarno sequence facilitating initiation on initator AUG (marked as start) and known to stimulate frameshifting. stop, stop codon in B.firmus cdd.