cd16453: RING-Ubox (this model, PSSM-Id:319367 is obsolete and has been replaced by 438117)
U-box domain, a modified RING finger
The U-box protein family is a family of E3 enzymes that also includes the HECT family and the RING finger family. E3 enzyme is ubiquitin-protein ligase that cooperates with a ubiquitin-activating enzyme (E1) and a ubiquitin-conjugating enzyme (E2), and plays a central role in determining the specificity of the ubiquitination system. It removes the ubiquitin molecule from E2 enzyme and attaches it to the target substrate, forming a covalent bond between ubiquitin and the target. U-box proteins are characterized by the presence of a U-box domain of approximately 70 amino acids. U-box is a modified form of the RING finger domain that lacks metal chelating cysteines and histidines. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms.
Feature 1:U-box domain, a modified RING finger [structural motif]
Evidence:
Comment:The U-box is a modified form of the RING finger domain that lacks metal chelating cysteines and histidines. Like the RING finger, the U-box is thought to form a structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions.
Jiyao W et al.(2023). "The conserved domain database in 2023.",