PDBsum entry 2jwz

Signaling protein

PDB id: 2jwz

Contents

Protein chain

76 a.a. *

* Residue conservation analysis

PDB id:

2jwz

Name:

Signaling protein

Title:

Mutations in the hydrophobic core of ubiquitin differentially affect its recognition by receptor proteins

Structure:

Ubiquitin. Chain: a. Engineered: yes. Mutation: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Gene: ubi1, rpl40a. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

10 models

Authors:

A.Haririnia,R.Verma,N.Purohit,M.Twarog,R.Deshaies,D.Bolon,D.Fushman

Key ref:

A.Haririnia et al. (2008). Mutations in the hydrophobic core of ubiquitin differentially affect its recognition by receptor proteins. J Mol Biol, 375, 979-996. PubMed id: 18054791 DOI: 10.1016/j.jmb.2007.11.016

Date:

31-Oct-07 Release date: 08-Jan-08

Protein chain

P0CG63  (UBI4P_YEAST) -  Polyubiquitin from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 381 a.a.

Struc: 76 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/j.jmb.2007.11.016

J Mol Biol 375:979-996 (2008)

PubMed id: 18054791

Mutations in the hydrophobic core of ubiquitin differentially affect its recognition by receptor proteins.

A.Haririnia, R.Verma, N.Purohit, M.Z.Twarog, R.J.Deshaies, D.Bolon, D.Fushman.

ABSTRACT

Ubiquitin (Ub) is one of the most highly conserved signaling proteins in eukaryotes. In carrying out its myriad functions, Ub conjugated to substrate proteins interacts with dozens of receptor proteins that link the Ub signal to various biological outcomes. Here we report mutations in conserved residues of Ub's hydrophobic core that have surprisingly potent and specific effects on molecular recognition. Mutant Ubs bind tightly to the Ub-associated domain of the receptor proteins Rad23 and hHR23A but fail to bind the Ub-interacting motif present in the receptors Rpn10 and S5a. Moreover, chains assembled on target substrates with mutant Ubs are unable to support substrate degradation by the proteasome in vitro or sustain viability of yeast cells. The mutations have relatively little effect on Ub's overall structure but reduce its rigidity and cause a slight displacement of the C-terminal beta-sheet, thereby compromising association with Ub-interacting motif but not with Ub-associated domains. These studies emphasize an unexpected role for Ub's core in molecular recognition and suggest that the diversity of protein-protein interactions in which Ub engages placed enormous constraints on its evolvability.

Selected figure(s)

Figure 3.
Fig. 3. Functional in vitro assays. All assays were performed as described in Materials and Methods. (a) Single Ub mutants (L67S or L69S) could be charged by E1/E2 (Cdc34) and conjugated onto a substrate (MbpSic1) by SCF^Cdc4 to generate high-MW conjugates that are indistinguishable from WT Ub conjugates. (b) The high-MW conjugates generated from Ub mutants are not degraded by the 26S proteasome. (c) The mutant high-MW conjugates bind to Rad23 but not to Rpn10. (d) Mutant Ub could not be conjugated to the PYP reporter substrate using Rsp5 and Ubc4.

Figure 8.
Fig. 8. Structural superposition models show how the displacement of β5 in L69S could affect its binding to UIMs of S5a but not to UBAs of hHR23A. Shown is a superimposition of L69S Ub structure on the known structures of WT Ub complexes: (a) Ub:UIM-2 (PDB code 1YX6); (b) Ub:UBA-1; (c) Ub:UIM-1 (PDB code 1YX6); and (d) Ub:UBA-2. WT Ub is shown in blue, L69S Ub is in green, and the UIM or UBA domains are in red. The Ub:UIM structures are from Ref. 26, while the Ub:UBA docked models are from Ref. 28.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2008, 375, 979-996) copyright 2008.

Figures were selected by an automated process.