4IG7

Crystal structure of Trichinella spiralis UCH37 bound to Ubiquitin vinyl methyl ester


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 

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Literature

Stabilization of an Unusual Salt Bridge in Ubiquitin by the Extra C‑Terminal Domain of the Proteasome-Associated Deubiquitinase UCH37 as a Mechanism of Its Exo Specificity.

Morrow, M.E.Kim, M.-I.Ronau, J.A.Sheedlo, M.J.White, R.R.Chaney, J.Paul, L.N.Lill, M.A.Artavanis-Tsakonas, K.Das, C.

(2013) Biochemistry 52: 3564-3578

  • DOI: 10.1021/bi4003106
  • Primary Citation of Related Structures:  
    4I6N, 4IG7

  • PubMed Abstract: 
  • Ubiquitination is countered by a group of enzymes collectively called deubiquitinases (DUBs); ∼100 of them can be found in the human genome. One of the most interesting aspects of these enzymes is the ability of some members to selectively recognize ...

    Ubiquitination is countered by a group of enzymes collectively called deubiquitinases (DUBs); ∼100 of them can be found in the human genome. One of the most interesting aspects of these enzymes is the ability of some members to selectively recognize specific linkage types between ubiquitin in polyubiquitin chains and their endo and exo specificity. The structural basis of exo-specific deubiquitination catalyzed by a DUB is poorly understood. UCH37, a cysteine DUB conserved from fungi to humans, is a proteasome-associated factor that regulates the proteasome by sequentially cleaving polyubiquitin chains from their distal ends, i.e., by exo-specific deubiquitination. In addition to the catalytic domain, the DUB features a functionally uncharacterized UCH37-like domain (ULD), presumed to keep the enzyme in an inhibited state in its proteasome-free form. Herein we report the crystal structure of two constructs of UCH37 from Trichinella spiralis in complex with a ubiquitin-based suicide inhibitor, ubiquitin vinyl methyl ester (UbVME). These structures show that the ULD makes direct contact with ubiquitin stabilizing a highly unusual intramolecular salt bridge between Lys48 and Glu51 of ubiquitin, an interaction that would be favored only with the distal ubiquitin but not with the internal ones in a Lys48-linked polyubiquitin chain. An inspection of 39 DUB-ubiquitin structures in the Protein Data Bank reveals the uniqueness of the salt bridge in ubiquitin bound to UCH37, an interaction that disappears when the ULD is deleted, as revealed in the structure of the catalytic domain alone bound to UbVME. The structural data are consistent with previously reported mutational data on the mammalian enzyme, which, together with the fact that the ULD residues that bind to ubiquitin are conserved, points to a similar mechanism behind the exo specificity of the human enzyme. To the best of our knowledge, these data provide the only structural example so far of how the exo specificity of a DUB can be determined by its noncatalytic domain. Thus, our data show that, contrary to its proposed inhibitory role, the ULD actually contributes to substrate recognition and could be a major determinant of the proteasome-associated function of UCH37. Moreover, our structures show that the unproductively oriented catalytic cysteine in the free enzyme is aligned correctly when ubiquitin binds, suggesting a mechanism for ubiquitin selectivity.


    Organizational Affiliation

    Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Ubiquitin C-terminal hydrolase 37A343Trichinella spiralisMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
UbiquitinB75Homo sapiensMutation(s): 0 
Gene Names: UBC
Find proteins for P0CG48 (Homo sapiens)
Explore P0CG48 
Go to UniProtKB:  P0CG48
NIH Common Fund Data Resources
PHAROS  P0CG48
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GVE
Query on GVE

Download CCD File 
B
METHYL 4-AMINOBUTANOATE
C5 H11 N O2
KVQGGLZHHFGHPU-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 147.361α = 90
b = 147.361β = 90
c = 40.485γ = 120
Software Package:
Software NamePurpose
HKL-3000data collection
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-05-29
    Type: Initial release
  • Version 1.1: 2014-01-15
    Changes: Database references