Acts as a chaperone. Associates tightly with 30S ribosome subunits (PubMed:8359926, PubMed:9766227). Probably on the external side of the cell wall (By similarity). Present in cells grown on plates but not in those grown in shaken liquid culture (at protein level). Induced in the absence of oxygen (hypoxia) (at protein level). Belongs to the small heat shock protein (HSP20) family.