Serpin (serine protease inhibitor) | |||||||||||
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![]() A serpin (white) with its 'reactive centre loop' (blue) bound to a protease (grey). Once the protease attempts catalysis it will be irreversibly inhibited. (PDB: 1K9O) | |||||||||||
Identifiers | |||||||||||
Symbol | Serpin, SERPIN (root symbol of family) | ||||||||||
Pfam | PF00079 | ||||||||||
InterPro | IPR000215 | ||||||||||
PROSITE | PDOC00256 | ||||||||||
SCOP2 | 1hle / SCOPe / SUPFAM | ||||||||||
CDD | cd00172 | ||||||||||
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Serpins are a superfamily of proteins with similar structures that were first identified for their protease inhibition activity and are found in all kingdoms of life.[1][2] The acronym serpin was originally coined because the first serpins to be identified act on chymotrypsin-like serine proteases (serine protease inhibitors).[3][4][5] They are notable for their unusual mechanism of action, in which they irreversibly inhibit their target protease by undergoing a large conformational change to disrupt the target's active site.[6][7] This contrasts with the more common competitive mechanism for protease inhibitors that bind to and block access to the protease active site.[8][9]
Protease inhibition by serpins controls an array of biological processes, including coagulation and inflammation, and consequently these proteins are the target of medical research.[10] Their unique conformational change also makes them of interest to the structural biology and protein folding research communities.[7][8] The conformational-change mechanism confers certain advantages, but it also has drawbacks: serpins are vulnerable to mutations that can result in serpinopathies such as protein misfolding and the formation of inactive long-chain polymers.[11][12] Serpin polymerisation not only reduces the amount of active inhibitor, but also leads to accumulation of the polymers, causing cell death and organ failure.[10]
Although most serpins control proteolytic cascades, some proteins with a serpin structure are not enzyme inhibitors, but instead perform diverse functions such as storage (as in egg white—ovalbumin), transport as in hormone carriage proteins (thyroxine-binding globulin, cortisol-binding globulin) and molecular chaperoning (HSP47).[9] The term serpin is used to describe these members as well, despite their non-inhibitory function, since they are evolutionarily related.[1]
Silverman_2001
was invoked but never defined (see the help page).Law_2006
was invoked but never defined (see the help page).Carrell_1997
was invoked but never defined (see the help page).