ATP-dependent proteinases in bacteria.

Cytoplasmic proteolysis is an indispensable process for proper function of a cell. Degradation of many intracellular proteins is initiated by ATP-dependent proteinases, which are involved in the regulation of the level of proteins with short half-lives. In addition, they remove many damaged and abnormal proteins and thus play also an important role during stress. ATP-dependent proteinases are large multi-subunit assemblies composed of proteolytic core domains and ATPase-containing regulatory domains on a single polypeptide chain or on distinct subunits, which can act as molecular chaperones. This review briefly summarizes the data about four main groups of these proteinases in bacteria (i.e. Lon, Clp family, HslUV and FtsH) and characterizes their structure, mechanism of action and properties.