The 30S, small subunit of the bacterial ribosome is comprised of one large ribosomal RNA (rRNA), 16S rRNA, and about 21 unique ribosomal proteins (r-proteins: S1–S21). S15 is a primary binding protein that plays a pivotal role in the assembly of ribosomal proteins S6, S11, S18, and S21 with the central domain of 16S ribosomal RNA to form the platform of the 30S subunit. 30S subunits lacking S15 appear to be somewhat defective in subunit association in vivo and in vitro. S15 regulates its own expression by a feedback mechanism at the translational level. The presented structure of C. jejuni S15 shows unique ‘unfolded’ conformation compared to previously known S15 structures.