P0CG47

Ubiquitin is a highly conserved small protein composed of 76 amino acids, characterized by a compact, beta-grasp fold that is crucial for interacting with cellular proteins and enzymes. This structural integrity allows Ubiquitin to form covalent isopeptide bonds with lysine residues on target proteins, facilitating polyubiquitin chain formation essential for signaling pathways related to protein degradation, DNA repair, and cell cycle regulation. The ability of Ubiquitin to adopt different conformations enables tagging abnormal, foreign, and improperly folded proteins for degradation by the 26S Proteasome, maintaining cellular homeostasis and protein quality control. Additionally, Ubiquitin′s structural features enable participation in signal transduction cascade regulation by modulating stability and activity of key regulatory proteins such as IκB-α and p27.