Proteasome alpha-subunit, N-terminal domain
IPR000426
Definition
The proteasome (or macropain) ([ec:3.4.25.1]) [[cite:PMID:7682410], [cite:PMID:2643381], [cite:PMID:1317508], [cite:PMID:7697118], [cite:PMID:8882582]] is a multicatalytic proteinase complex in eukaryotes and archaea, and in some bacteria, that is involved in an ATP/ubiquitin-dependent non-lysosomal proteolytic pathway. In eukaryotes the 20S proteasome is composed of 28 distinct subunits which form a highly ordered ring-shaped structure (20S ring) of about 700kDa. Proteasome subunits can be classified on the basis of sequence similarities into two groups, alpha (A) and beta (B). The proteasome consists of four stacked rings composed of α/β/β/α subunits. There are seven different alpha subunits and seven different beta subunits PMID:9087403. Three of the seven beta subunits are peptidases, each with a different specificity. Subunit beta1c (MEROPS identifier T01.010) has a preference for cleaving glutaminyl bonds ("peptidyl-glutamyl-like" or "caspase-like"), subunit beta2c (MEROPS identifier T01.011) has a preference for cleaving arginyl and lysyl bonds ("trypsin-like"), and subunit beta5c (MEROPS identifier T01.012) cleaves after hydrophobic amino acids ("chymotrypsin-like") PMID:2535672. The proteasome subunits are related to N-terminal nucleophile hydrolases, and the catalytic subunits have an N-terminal threonine nucleophile. Subunits that belong to the A group are proteins of from 210 to 290 amino acids. They are classified as non-peptidase homologues in MEROPS peptidase family T1 (clan PB(T)).
8 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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