Endopeptidase Clp (, ''endopeptidase Ti'', ''caseinolytic protease'', ''protease Ti'', ''ATP-dependent Clp protease'', '' ClpP'', ''Clp protease''). This enzyme catalyses the following

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

Hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

of proteins to small

peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...

s in the presence of ATP and Mg²⁺. This bacterial enzyme contains subunits of two types, ClpP, with

peptidase A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do ...

activity, and the protein ClpA, with

AAA+ AAA, Triple A, or Triple-A is a three-letter initialism or abbreviation which may refer to: Arts, entertainment, and media Gaming * AAA (video game industry) - a category of high budget video games *'' TripleA'', an open source wargame Mu ...

ATPase ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, ATP hydrolase, adenosine triphosphatase) are a class of enzymes that catalyze the decomposition of ATP into ADP and a free phosphate ion or ...

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). 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. ClpYQ is another name for the HslVU complex, a

heat shock protein Heat shock proteins (HSPs) are a family of proteins produced by cells in response to exposure to stressful conditions. They were first described in relation to heat shock, but are now known to also be expressed during other stresses including ex ...

complex thought to resemble the hypothetical ancestor of the

proteasome Proteasomes are essential protein complexes responsible for the degradation of proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that help such reactions are called proteases. Proteasomes are found inside all e ...

ATPase

The Hsp100 family of eukaryotic heat shock proteins is homologous to the ATPase-active chaperon subunits found in the Clp complex; as such the entire group is often referred to as the HSP100/Clp family. The family is usually broken into two parts, one being the ClpA/B family with two ATPase domains, and the other being ClpX and friends with only one such domain. ClpA through E is put into the first group along with Hsp78/104, and ClpX and HSIU is put into the second group. Many of the proteins are not associated with a protease and have functions other than proteolysis. ClpB (human CLPB "Hsp78", yeast

Hsp104 Hsp104 is a heat-shock protein. It is known to reverse toxicity of mutant α-synuclein, TDP-43, FUS (gene), FUS, and TAF15 in yeast cells. Conserved in prokaryotes (ClpB), fungi, plants and as well as animal mitochondria, there is yet to see hsp10 ...

) break up insoluble protein aggregates in conjunction with DnaK/

Hsp70 The 70 kilodalton heat shock proteins (Hsp70s or DnaK) are a family of conserved ubiquitously expressed heat shock proteins. Proteins with similar structure exist in virtually all living organisms and play crucial roles in the development of can ...

. They are thought to function by threading client proteins through a small 20 Å (2 nm) pore, thereby giving each client protein a second chance to fold. A member of the ClpA/B family termed ClpV is used in the bacterial T6SS.

References

External links

* {{Portal bar, Biology, border=no EC 3.4.21

ATPase

See also

References

External links