Summary: Potato inhibitor I family
Potato inhibitor I family Provide feedback
No Pfam abstract.
Internal database links
|Similarity to PfamA using HHSearch:||Inhibitor_I78|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR000864
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.
This family of proteinase inhibitors belong to MEROPS inhibitor family I13, clan IG. They inhibit peptidases of the S1 (INTERPRO) and S8 (INTERPRO) families [PUBMED:14705960]. Potato inhibitor type I sequences are not solely restricted to potatoes but are found in other plant species for example: barley endosperm chymotrypsin inhibitor [PUBMED:3106042], and pumpkin trypsin inhibitor. Exceptions are found in leech's, e.g.Hirudo medicinalis (Medicinal leech), but not other metazoa [PUBMED:3519213]. In general, the proteins have retained a specificity towards chymotrypsin-like and elastase-like proteases [PUBMED:]. Structurally these inhibitors are small (60 to 90 residues) and in contrast with other families of protease inhibitors, they lack disulphide bonds. The inhibitor is a wedge-shaped molecule, its pointed edge formed by the protease-binding loop, which contains the scissile bond. The loop binds tightly to the protease active site, subsequent cleavage of the scissile bond causing inhibition of the enzyme [PUBMED:3519213].
The inhibitors (designated type I and II) are synthesised in potato tubers, increasing in concentration as the tuber develops. Synthesis of the inhibitors throughout the plant is also induced by leaf damage; this systemic response being triggered by the release of a putative plant hormone [PUBMED:].
Examples found in the bacteria and archaea are probable false positives.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||serine-type endopeptidase inhibitor activity (GO:0004867)|
|Biological process||response to wounding (GO:0009611)|
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Curation and family details
|Number in seed:||60|
|Number in full:||372|
|Average length of the domain:||61.90 aa|
|Average identity of full alignment:||42 %|
|Average coverage of the sequence by the domain:||75.93 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||13|
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There are 2 interactions for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the potato_inhibit domain has been found. There are 54 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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