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 IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

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. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

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 (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the fo ...

activity, and the protein ClpA, with

AAA+ AAA, Triple A, or Triple-A is a three-letter initialism or abbreviation which may refer to: Airports * Anaa Airport in French Polynesia (IATA airport code AAA) * Logan County Airport (Illinois) (FAA airport code AAA) Arts, entertainment, and me ...

ATPase ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are ...

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 The heat shock proteins HslV and HslU (HslVU complex; also known as ClpQ and ClpY respectively, or ClpQY) are expressed in many bacteria such as '' E. coli'' in response to cell stress.Ramachandran R, Hartmann C, Song HK, Huber R, Bochtler M. (2 ...

complex, a

heat shock protein Heat shock proteins (HSP) 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 expo ...

complex thought to resemble the hypothetical ancestor of the

proteasome Proteasomes are protein complexes which degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that help such reactions are called proteases. Proteasomes are part of a major mechanism by w ...

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 Caseinolytic peptidase B protein homolog (''CLPB''), also known as Skd3, is a mitochondrial AAA ATPase chaperone that in humans is encoded by the gene ''CLPB'', which encodes an adenosine triphosphate-(ATP) dependent chaperone. Skd3 is localized ...

"Hsp78", yeast

Hsp104 Hsp104 is a heat-shock protein. It is known to reverse toxicity of mutant α-synuclein, TDP-43, FUS, and TAF15 in yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast origin ...

) 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. Intracellularly localized Hsp70s are an importa ...

. 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 The type VI secretion system (T6SS) is molecular machine used by a wide range of Gram-negative bacterial species to transport effectors from the interior (cytoplasm or cytosol) of a bacterial cell across the cellular envelope into an adjacent targe ...

References

External links

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

ATPase

See also

References

External links