2QJ0

Structure of the yeast U-box-containing ubiquitin ligase Ufd2p

Summary for 2QJ0

• Entry DOI: 10.2210/pdb2qj0/pdb
• Related: 2QIZ
• Descriptor: Ubiquitin conjugation factor E4 (2 entities in total)
• Functional Keywords: helical hairpin, ligase
• Biological source: Saccharomyces cerevisiae (baker's yeast)
• Cellular location: Cytoplasm: P54860
• Total number of polymer chains: 1
• Total formula weight: 113213.79

Authors

Tu, D.,Brunger, A.T. (deposition date: 2007-07-06, release date: 2007-09-18, Last modification date: 2021-10-20)

Primary citation

Tu, D.,Li, W.,Ye, Y.,Brunger, A.T.
Inaugural Article: Structure and function of the yeast U-box-containing ubiquitin ligase Ufd2p.
Proc.Natl.Acad.Sci.Usa, 104:15599-15606, 2007

PubMed Abstract: Proteins conjugated by Lys-48-linked polyubiquitin chains are preferred substrates of the eukaryotic proteasome. Polyubiquitination requires an activating enzyme (E1), a conjugating enzyme (E2), and a ligase (E3). Occasionally, these enzymes only assemble short ubiquitin oligomers, and their extension to full length involves a ubiquitin elongating factor termed E4. Ufd2p, as the first E4 identified to date, is involved in the degradation of misfolded proteins of the endoplasmic reticulum and of a ubiquitin-beta-GAL fusion substrate in Saccharomyces cerevisiae. The mechanism of action of Ufd2p is unknown. Here we describe the crystal structure of the full-length yeast Ufd2p protein. Ufd2p has an elongated shape consisting of several irregular Armadillo-like repeats with two helical hairpins protruding from it and a U-box domain flexibly attached to its C terminus. The U-box of Ufd2p has a fold similar to that of the RING (Really Interesting New Gene) domain that is present in certain ubiquitin ligases. Accordingly, Ufd2p has all of the hallmarks of a RING finger-containing ubiquitin ligase: it associates with its cognate E2 Ubc4p via its U-box domain and catalyzes the transfer of ubiquitin from the E2 active site to Ufd2p itself or to an acceptor ubiquitin molecule to form unanchored diubiquitin oligomers. Thus, Ufd2p can function as a bona fide E3 ubiquitin ligase to promote ubiquitin chain elongation on a substrate.

PubMed: 17890322
DOI: 10.1073/pnas.0701369104

Experimental method

X-RAY DIFFRACTION (2.65 Å)