2YBF

Complex of Rad18 (Rad6 binding domain) with Rad6b

Summary for 2YBF

• Entry DOI: 10.2210/pdb2ybf/pdb
• Related: 1JAS 1NXA 2Y43 2Y4W 2YB6
• Descriptor: UBIQUITIN-CONJUGATING ENZYME E2 B, E3 UBIQUITIN-PROTEIN LIGASE RAD18, BETA-MERCAPTOETHANOL, ... (6 entities in total)
• Functional Keywords: ligase, e2 ubiquitin conjugating enzyme, e3 ubiquitin ligase, translesion synthesis, pcna ubiquitination
• Biological source: HOMO SAPIENS (HUMAN); More
• Cellular location: Cell membrane (By similarity): P63146; Nucleus (By similarity): Q9NS91
• Total number of polymer chains: 2
• Total formula weight: 20839.34

Authors

Hibbert, R.G.,Sixma, T.K. (deposition date: 2011-03-08, release date: 2011-04-20, Last modification date: 2023-12-20)

Primary citation

Hibbert, R.G.,Huang, A.,Boelens, R.,Sixma, T.K.
E3 Ligase Rad18 Promotes Monoubiquitination Rather Than Ubiquitin Chain Formation by E2 Enzyme Rad6.
Proc.Natl.Acad.Sci.USA, 108:5590-, 2011

PubMed Abstract: In ubiquitin conjugation, different combinations of E2 and E3 enzymes catalyse either monoubiquitination or ubiquitin chain formation. The E2/E3 complex Rad6/Rad18 exclusively monoubiquitinates the proliferating cell nuclear antigen (PCNA) to signal for "error prone" DNA damage tolerance, whereas a different set of conjugation enzymes is required for ubiquitin chain formation on PCNA. Here we show that human E2 enzyme Rad6b is intrinsically capable of catalyzing ubiquitin chain formation. This activity is prevented during PCNA ubiquitination by the interaction of Rad6 with E3 enzyme Rad18. Using NMR and X-ray crystallography we show that the R6BD of Rad18 inhibits this activity by competing with ubiquitin for a noncovalent "backside" binding site on Rad6. Our findings provide mechanistic insights into how E3 enzymes can regulate the ubiquitin conjugation process.

PubMed: 21422291
DOI: 10.1073/PNAS.1017516108

Experimental method

X-RAY DIFFRACTION (2 Å)