3pt3

Publication Abstract from PubMed

UBR5 ubiquitin ligase (also known as EDD, Rat100 or hHYD) is a member of the E3 protein family of HECT (homologous to E6-AP C-terminus) ligases as it contains a C-terminal HECT domain. In ubiquitination cascades involving E3s of the HECT class, ubiquitin is transferred from an associated E2 ubiquitin-conjugating enzyme to the acceptor cysteine of the HECT domain, which consists of structurally distinct N- and C-lobes connected by a flexible linker. Here, the high-resolution crystal structure of the C-lobe of the HECT domain of human UBR5 is presented. The structure reveals important features that are unique compared with other HECT domains. In particular, a distinct four-residue insert in the second helix elongates this helix, resulting in a strikingly different orientation of the preceding loop. This protruding loop is likely to contribute to specificity towards the E2 ubiquitin-conjugating enzyme UBCH4, which is an important functional partner of UBR5. Ubiquitination assays showed that the C-lobe of UBR5 is able to form a thioester-linked E3-ubiquitin complex, although it does not physically interact with UBCH4 in NMR experiments. This study contributes to a better understanding of UBR5 ubiquitination activity.

Structure of the HECT C-lobe of the UBR5 E3 ubiquitin ligase.,Matta-Camacho E, Kozlov G, Menade M, Gehring K Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Oct 1;68(Pt 10):1158-63., doi: 10.1107/S1744309112036937. Epub 2012 Sep 22. PMID:23027739^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.