Endopeptidase_Clp
Endopeptidase Clp (EC 3.4.21.92, endopeptidase Ti, caseinolytic protease, protease Ti, ATP-dependent Clp protease, ClpP, Clp protease).[1][2][3][4] This enzyme catalyses the following chemical reaction
- Hydrolysis of proteins to small peptides in the presence of ATP and Mg2+.
This bacterial enzyme contains subunits of two types, ClpP, with peptidase activity, and the protein ClpA, with AAA+ ATPase activity. ClpP and ClpA are not evolutionarily related.
A fully assembled Clp protease complex has a barrel-shaped structure in which two stacked heptameric ring of proteolytic subunits (ClpP or ClpQ) are either sandwiched between two rings or single-caped by one ring of hexameric ATPase-active chaperon subunits (ClpA, ClpC, ClpE, ClpX, ClpY, or others).[5]
ClpXP is presented in almost all bacteria while ClpA is found in the Gram-negative bacteria, ClpC in Gram-Positive bacteria and cyanobacteria. ClpAP, ClpXP and ClpYQ coexist in E. coli while only ClpXP complex in present in humans as mitochondrial enzymes.[5] ClpYQ is another name for the HslVU complex, a heat shock protein complex thought to resemble the hypothetical ancestor of the proteasome.[6]