This family consists of the 30S ribosomal proteins subunit S22 polypeptides. This polypeptide is 47 amino acids in length and has a molecular weight of about 5 kDa. The S22 subunit is a component of the stationary-phase-specific ribosomal protein and is assembled in the ribosomal particles in the stationary phase. This subunit along with other stationary-phase-specific ribosomal proteins result in compositional changes of ribosomes during the stationary phase. The significance of this change is not clear as yet.