EC Explorer

2.3.2.27

RING-type E3 ubiquitin transferase

[E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-N⁶-ubiquitinyl-L-lysine

RING E3 ligase (misleading), ubiquitin transferase RING E3, S-ubiquitinyl-[ubiquitin-conjugating E2 enzyme]-L-cysteine:acceptor protein ubiquitin transferase (isopeptide bond-forming, RING-type)

[E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine:[acceptor protein] ubiquitin transferase (isopeptide bond-forming; RING-type)

RING E3 ubiquitin transferases serve as mediators bringing the ubiquitin-charged E2 ubiquitin-conjugating enzyme (EC 2.3.2.23) and an acceptor protein together to enable the direct transfer of ubiquitin through the formation of an isopeptide bond between the C-terminal glycine residue of ubiquitin and the ε-amino group of an L-lysine residue of the acceptor protein. Unlike EC 2.3.2.26, HECT-type E3 ubiquitin transferase, the RING-E3 domain does not form a catalytic thioester intermediate with ubiquitin. Many members of the RING-type E3 ubiquitin transferase family are not able to bind a substrate directly, and form a complex with a cullin scaffold protein and a substrate recognition module (the complexes are named CRL for Cullin-RING-Ligase). In these complexes, the RING-type E3 ubiquitin transferase provides an additional function, mediating the transfer of a NEDD8 protein from a dedicated E2 carrier to the cullin protein (see EC 2.3.2.32, cullin-RING-type E3 NEDD8 transferase). cf. EC 2.3.2.31, RBR-type E3 ubiquitin transferase.

created 2015, modified 2017