Analysis of the promoter region and the 5′ untranslated region of the arcABC operon. (A) Primer extension experiments with 10 μg (lane 1) and 15 μg (lane 2) of heat-induced (42°C) RNA of S. suis strain I9841/1. (B) Sequence of the promoter region of the S. suis arcABC operon. The transcriptional start point (arrow), the predicted −10 and −35 boxes, the predicted ARG box, the predicted Fnr-binding site, the predicted cre-binding sites, and the predicted Shine-Dalgarno (SD) sequence of arcA are indicated.