Experimental Data Snapshot

  • Resolution: 2.93 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 

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This is version 1.3 of the entry. See complete history


Crystal structure of a class I ubiquitin conjugating enzyme (Ubc7) from Saccharomyces cerevisiae at 2.9 angstroms resolution.

Cook, W.J.Martin, P.D.Edwards, B.F.Yamazaki, R.K.Chau, V.

(1997) Biochemistry 36: 1621-1627

  • DOI: https://doi.org/10.1021/bi962639e
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Ubiquitin-conjugating enzymes are a family of related proteins that participate in the ubiquitination of proteins. Previous studies on the crystal structures of Saccharomyces cerevisiae Ubc4 and Arabidopsis thaliana Ubc1 indicated that the smallest enzymes (class I), which consist entirely of the conserved core domain, share a common tertiary fold. Here we report the three-dimensional structure of the S. cerevisiae class I enzyme encoded by the UBC7 gene. The crystal structure has been solved using molecular replacement techniques and refined by simulated annealing to an R-factor of 0.183 at 2.93 A resolution. Bond lengths and angles in the molecule have root-mean-square deviations from ideal values of 0.016 A and 2.3 degrees, respectively. Ubc7 is an alpha/beta protein with four alpha-helices and a four-stranded antiparallel beta-sheet. With the exception of two regions where extra residues are present, the tertiary folding of Ubc7 is similar to those of the other two enzymes. The ubiquitin-accepting cysteine is located in a cleft between two loops. One of these loops is nonconserved, as this region of the Ubc7 molecule differs from the other two enzymes by having 13 extra residues. There is also a second single amino acid insertion that alters the orientation of the turn between the first two beta-strands. Analysis of the 13 ubiquitin-conjugating enzyme sequences in S. cerevisiae indicates that there may be two other regions where extra residues could be inserted into the common tertiary fold. Both of these other regions exhibit significant deviations in the superposition of the three structures and, like the two insertion regions in Ubc7, may represent hypervariable regions within a common tertiary fold. As ubiquitin-conjugating enzymes interact with different substrates or other accessory proteins in the ubiquitination pathway, these variable surface regions may confer distinct specificity to individual enzymes.

  • Organizational Affiliation

    Department of Pathology, University of Alabama at Birmingham 35253, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
UBIQUITIN CONJUGATING ENZYME165Saccharomyces cerevisiaeMutation(s): 0 
Gene Names: UBC7
Find proteins for Q02159 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore Q02159 
Go to UniProtKB:  Q02159
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ02159
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.93 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.5α = 90
b = 106.5β = 90
c = 49.3γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
XENGENdata reduction
XENGENdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-03-18
    Type: Initial release
  • Version 1.1: 2008-03-25
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-09
    Changes: Database references, Other, Refinement description