User:Michelle Meyer BC/S15

First identified in Bacillus stearothermophilus, (now Geobacillus stearothermophilus, the RNA structure identified in leader sequences for S15 ribosomal proteins in Firmicutes is completely different from that identified in E. coli and other Gammaproteobacteria [RF00114]. The Firmicute S15 binding structure consists of a 3-helix junction that overlaps with the ‘AUG’ start of the rpsO coding region. Like its E. coli counterpart, it lies directly upstream of its binding partner, rpsO, and regulates only rpsO.

This RNA structure is widespread across Firmicutes, appearing in most Bacilli species and Negativiticutes, but has a lower incidence rate in Clostridia. Both the closing stem and helix 2 show nucleotide variability, and the final helix, H3, contains a conserved ‘GGAGG’ that is most likely part of the Shine-Delgarno sequence given that it’s position slightly upstream of the ‘AUG’ coding region start site for rpsO.