Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.204 

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Crystal structure of a staphylokinase: variant a model for reduced antigenicity.

Chen, Y.Song, G.Jiang, F.Feng, L.Zhang, X.Ding, Y.Bartlam, M.Yang, A.Ma, X.Ye, S.Liu, Y.Tang, H.Song, H.Rao, Z.

(2002) Eur J Biochem 269: 705-711

  • DOI: https://doi.org/10.1046/j.0014-2956.2001.02706.x
  • Primary Citation of Related Structures:  
    1C77, 1C78, 1C79

  • PubMed Abstract: 

    Staphylokinase (SAK) is a 15.5-kDa protein from Staphylococcus aureus that activates plasminogen by forming a 1 : 1 complex with plasmin. Recombinant SAK has been shown in clinical trials to induce fibrin-specific clot lysis in patients with acute myocardial infarction. However, SAK elicits high titers of neutralizing antibodies. Biochemical and protein engineering studies have demonstrated the feasibility of generating SAK variants with reduced antigenicity yet intact thrombolytic potency. Here, we present X-ray crystallographic evidence that the SAK(S41G) mutant may assume a dimeric structure. This dimer model, at 2.3-A resolution, could explain a major antigenic epitope (residues A72-F76 and residues K135-K136) located in the vicinity of the dimer interface as identified by phage-display. These results suggest that SAK antigenicity may be reduced by eliminating dimer formation. We propose several potential mutation sites at the dimer interface that may further reduce the antigenicity of SAK.

  • Organizational Affiliation

    Laboratory of Structural Biology, MOE Laboratory of Protein Science, Tsinghua University, Beijing, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
136Staphylococcus aureusMutation(s): 0 
Gene Names: sak
Find proteins for P68802 (Staphylococcus aureus)
Explore P68802 
Go to UniProtKB:  P68802
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68802
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.87α = 90
b = 59.26β = 90
c = 102.42γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-08-01
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance