Conserved Site

Ubiquitin-activating enzyme E1, conserved site (IPR018074)

Short name: UBQ-activ_enz_E1_CS


Ubiquitin-activating enzyme (E1 enzyme) [PMID: 1647207, PMID: 1656558] activates ubiquitin by first adenylating with ATP its C-terminal glycine residue and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding an ubiquitin-E1 thiolester and free AMP. Later the ubiquitin moiety is transferred to a cysteine residue on one of the many forms of ubiquitin- conjugating enzymes (E2).

E1 is a large monomeric protein of about 110 to 115 Kd (about 1000 residues). In yeast there are two forms (UBA1 and UBA2) [PMID: 7629121], while in plants and mammals multiple forms exist including a form which is Y-linked in mouse and some other mammals and which may be involved in spermatogenesis.

It has been shown that the last of the five cysteines that are conserved in the sequence of E1 from various species is the one that binds ubiquitin [PMID: 1634524]. This entry represents a conserved region containing the second of the five conserved cysteines.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns