| Primary Identifier | IPR000626 | Type | Domain |
| Short Name | Ubiquitin-like_dom |
| description | Ubiquitin is a protein of 76 amino acid residues, found in all eukaryotic cells and whose sequence is extremely well conserved from protozoan to vertebrates. Ubiquitin acts through its post-translational attachment (ubiquitinylation) to other proteins, where these modifications alter the function, location or trafficking of the protein, or targets it for destruction by the 26S proteasome [].Ubiquitin is a globular protein, the last four C-terminal residues (Leu-Arg-Gly-Gly) extending from the compact structure to form a 'tail', important for its function. The latter is mediated by the covalent conjugation of ubiquitin to target proteins, by an isopeptide linkage between the C-terminal glycine and the epsilon amino group of lysine residues in the target proteins.Ubiquitin is expressed as three different precursors: a polymeric head-to-tail concatemer of identical units (polyubiquitin), and two N-terminal ubiquitin moieties, UbL40 and UbS27, that are fused to the ribosomal polypeptides L40 and S27, respectively. Specific endopeptidases cleave these precursor molecules []to release ubiquitin moieties that are identical in sequence and contribute to the ubiquitin pool []. Some organisms express additional ubiquitin fusion proteins []. Furthermore, there are several ubiquitin-like proteins derived from ubiquitin [].This entry represents a domain characteristic of ubiquitin (Ub) and ubiquitin-like (Ubl) proteins such as SUMO [, ]and Nedd8 []. |
