Crystal structure of the four N-terminal immunoglogulin domains of Sidekick-2 protein

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.284 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Architecture of cell-cell adhesion mediated by sidekicks.

Tang, H.Chang, H.Dong, Y.Guo, L.Shi, X.Wu, Y.Huang, Y.He, Y.

(2018) Proc Natl Acad Sci U S A 115: 9246-9251

  • DOI: https://doi.org/10.1073/pnas.1801810115
  • Primary Citation of Related Structures:  
    5XWX, 5XX0

  • PubMed Abstract: 

    Cell-cell adhesion is important for cell growth, tissue development, and neural network formation. Structures of cell adhesion molecules have been widely studied by crystallography, revealing the molecular details of adhesion interfaces. However, due to technical limitations, the overall structure and organization of adhesion molecules at cell adhesion interfaces has not been fully investigated. Here, we combine electron microscopy and other biophysical methods to characterize the structure of cell-cell adhesion mediated by the cell adhesion molecule Sidekick (Sidekick-1 and Sidekick-2) and obtain 3D views of the Sidekick-mediated adhesion interfaces as well as the organization of Sidekick molecules between cell membranes by electron tomography. The results suggest that the Ig-like domains and the fibronectin III (FnIII) domains of Sidekicks play different roles in cell adhesion. The Ig-like domains mediate the homophilic transinteractions bridging adjacent cells, while the FnIII domains interact with membranes, resulting in a tight adhesion interface between cells that may contribute to the specificity and plasticity of cell-cell contacts during cell growth and neural development.

  • Organizational Affiliation

    State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences 201210 Shanghai, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protein sidekick-2
A, B
403Mus musculusMutation(s): 0 
Gene Names: Sdk2Kiaa1514
Find proteins for Q6V4S5 (Mus musculus)
Explore Q6V4S5 
Go to UniProtKB:  Q6V4S5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6V4S5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.284 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.356α = 90
b = 86.801β = 90
c = 108.553γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-08-29
    Type: Initial release
  • Version 1.1: 2018-09-19
    Changes: Data collection, Database references
  • Version 1.2: 2018-09-26
    Changes: Data collection, Database references
  • Version 1.3: 2023-11-22
    Changes: Data collection, Database references, Refinement description