HECT Protein Domain

The HECT domain of E6AP ubiquitin-protein ligase.

Domain Binding and Function

The HECT domain (Homologous to the E6-AP Carboxyl Terminus) is an approximately 40 kDa (350 amino acid) catalytic domain found at the carboxy-terminus of HECT-class E3 ubiquitin protein ligases. This domain binds specific E2 enzymes, accepts ubiquitin from E2 to form an ubiquitin-thioester intermediate with the HECT active cysteine, and then transfers ubiquitin to either the ε-amino groups of lysine side chains of the substrate or to the growing end of multiubiquitin chains. The formation of a thioester intermediate with ubiquitin is unique to HECT E3 ligases and is not seen with other types of E3 ligase.

Structure Reference

1. Huang, L. et al. (1999) Science 286 (5443), 1321–1326.

Examples of Domain Proteins

Binding Examples