cl00154

Ubiquitin-conjugating enzyme E2, catalytic (UBCc) domain. This is part of the ubiquitin-mediated protein degradation pathway in which a thiol-ester linkage forms between a conserved cysteine and the C-terminus of ubiquitin and complexes with ubiquitin protein ligase enzymes, E3. This pathway regulates many fundamental cellular processes. There are also other E2s which form thiol-ester linkages without the use of E3s as well as several UBC homologs (TSG101, Mms2, Croc-1 and similar proteins) which lack the active site cysteine essential for ubiquitination and appear to function in DNA repair pathways which were omitted from the scope of this CD.