InterPro domain: IPR000594

Ubiquitin-activating enzyme (E1 enzyme) [ 1 , 2 ] activates ubiquitin by firstadenylating with ATP its C-terminal glycine residue and thereafter linkingthis residue to the side chain of a cysteine residue in E1, yielding anubiquitin-E1 thiolester and free AMP. Later the ubiquitin moiety istransferred to a cysteine residue on one of the many forms of ubiquitin-conjugating enzymes (E2).

This domain is a NAD/FAD-binding fold found in ubiquitin activating E1 family and members of the bacterial ThiF/MoeB/HesA family. It is repeated in Ubiquitin-activating enzyme E1 [ 3 , 4 , 5 ].

1. Genetic analysis of the ubiquitin system. Biochim. Biophys. Acta 1089, 127-39
2. The ubiquitin pathway for protein degradation. Trends Biochem. Sci. 16, 265-8
3. Mechanism of ubiquitin activation revealed by the structure of a bacterial MoeB-MoaD complex. Nature 414, 325-9
4. Structures of the SUMO E1 provide mechanistic insights into SUMO activation and E2 recruitment to E1. EMBO J. 24, 439-51
5. Structural insights into E1-catalyzed ubiquitin activation and transfer to conjugating enzymes. Cell 134, 268-78