PDBsum entry 2y43

Ligase

PDB id

2y43

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Contents

			Protein chain

					89 a.a.

			Metals

					_ZN ×4

			Waters ×102

PDB id:

2y43

Links

Name:

Ligase

Title:

Rad18 ubiquitin ligase ring domain structure

Structure:

E3 ubiquitin-protein ligase rad18. Chain: a, b. Fragment: ring domain, residues 1-99. Synonym: rad18, postreplication repair protein rad18, ring finger protein 73, hhr18, hrad18. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.80Å

R-factor:

0.177

R-free:

0.223

Authors:

R.G.Hibbert,T.K.Sixma

Key ref:

A.Huang et al. (2011). Symmetry and asymmetry of the RING-RING dimer of Rad18. J Mol Biol, 410, 424-435. PubMed id: 21549715 DOI: 10.1016/j.jmb.2011.04.051

Date:

04-Jan-11

Release date:

11-May-11

PROCHECK

	Headers

	References

Protein chains

Q9NS91 (RAD18_HUMAN) - E3 ubiquitin-protein ligase RAD18 from Homo sapiens

Seq: Struc:					495 a.a. 89 a.a.

Key:

PfamA domain

Secondary structure

CATH domain



		Enzyme reactions

Enzyme class:

E.C.2.3.2.27 - RING-type E3 ubiquitin transferase.

[IntEnz] [ExPASy] [KEGG] [BRENDA]

Reaction:

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

DOI no: 10.1016/j.jmb.2011.04.051	J Mol Biol 410:424-435 (2011)
PubMed id: 21549715

Symmetry and asymmetry of the RING-RING dimer of Rad18.
A.Huang, R.G.Hibbert, R.N.de Jong, D.Das, T.K.Sixma, R.Boelens.

ABSTRACT

The human ubiquitin-conjugating enzyme Rad6 (E2), with ubiquitin ligase enzyme Rad18 (RING E3), monoubiquitinates proliferating cell nuclear antigen at stalled replication forks in DNA translesion synthesis. Here, we determine the structure of the homodimeric Rad18 RING domains by X-ray crystallography and classify it to RING-RING dimers that dimerize through helices adjacent to the RING domains and through the canonical RING domains. Using NMR spectroscopy and site-directed mutagenesis, we demonstrate that the Rad6b binding site, for the Rad18 RING domain, strongly resembles that of other E2/E3 RING/U-box complexes. We show that the homodimeric Rad18 RING domain can recruit two Rad6b E2 enzymes, whereas the full-length Rad18 homodimer binds only to a single Rad6b molecule. Such asymmetry is a common feature of RING-RING heterodimers and has been observed for the CHIP U-box homodimer. We propose that asymmetry may be a common feature of dimeric RING E3 ligases.