2YB6 image
Deposition Date 2011-03-02
Release Date 2011-04-20
Last Version Date 2023-12-20
Entry Detail
PDB ID:
2YB6
Keywords:
Title:
Native human Rad6
Biological Source:
Source Organism:
HOMO SAPIENS (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.50 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 43 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:UBIQUITIN-CONJUGATING ENZYME E2 B
Gene (Uniprot):UBE2B
Chain IDs:A
Chain Length:152
Number of Molecules:1
Biological Source:HOMO SAPIENS
Primary Citation
E3 Ligase Rad18 Promotes Monoubiquitination Rather Than Ubiquitin Chain Formation by E2 Enzyme Rad6.
Proc.Natl.Acad.Sci.USA 108 5590 ? (2011)
PMID: 21422291 DOI: 10.1073/PNAS.1017516108

Abstact

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.

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