Inhibitor_I29Cathepsin propeptide inhibitor domain (I29)
|SMART accession number:||SM00848|
|Description:||This domain is found at the N-terminus of some C1 peptidases such as Cathepsin L where it acts as a propeptide. There are also a number of proteins that are composed solely of multiple copies of this domain such as the peptidase inhibitor salarin. This family is classified as I29 by MEROPS. Peptide proteinase inhibitors can be found as single domain proteins or as single or multiple domains within proteins; these are referred to as either simple or compound inhibitors, respectively. In many cases they are synthesised as part of a larger precursor protein, either as a prepropeptide or as an N-terminal domain associated with an inactive peptidase or zymogen. This domain prevents access of the substrate to the active site. Removal of the N-terminal inhibitor domain either by interaction with a second peptidase or by autocatalytic cleavage activates the zymogen. Other inhibitors interact direct with proteinases using a simple noncovalent lock and key mechanism; while yet others use a conformational change-based trapping mechanism that depends on their structural and thermodynamic properties.|
|Interpro abstract (IPR013201):|
This entry represents a peptidase inhibitor domain, which belongs to MEROPS peptidase inhibitor family I29. The domain is also found at the N terminus of a variety of peptidase precursors that belong to MEROPS peptidase subfamily C1A; these include cathepsin L, papain, and procaricain (P10056) [(PUBMED:8939744)]. It forms an alpha-helical domain that runs through the substrate-binding site, preventing access. Removal of this region by proteolytic cleavage results in activation of the enzyme. This domain is also found, in one or more copies, in a variety of cysteine peptidase inhibitors such as salarin [(PUBMED:14505823)].
Click on the following links for more information.
- Evolution (species in which this domain is found)
- Cellular role (predicted cellular role)
- Metabolism (metabolic pathways involving proteins which contain this domain)
- Structure (3D structures containing this domain)
- Links (links to other resources describing this domain)