5K6Y

Sidekick-2 immunoglobulin domains 1-4, crystal form 2

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history. 


Literature

Molecular basis of sidekick-mediated cell-cell adhesion and specificity.

Goodman, K.M., Yamagata, M., Jin, X., Mannepalli, S., Katsamba, P.S., Ahlsen, G., Sergeeva, A.P., Honig, B., Sanes, J.R., Shapiro, L.

(2016) Elife 5

  • DOI: https://doi.org/10.7554/eLife.19058
  • Primary Citation of Related Structures:  
    5K6U, 5K6V, 5K6W, 5K6X, 5K6Y, 5K6Z, 5K70

  • PubMed Abstract: 

    • Sidekick (Sdk) 1 and 2 are related immunoglobulin superfamily cell adhesion proteins required for appropriate synaptic connections between specific subtypes of retinal neurons. Sdks mediate cell-cell adhesion with homophilic specificity that underlies their neuronal targeting function ...

    Sidekick (Sdk) 1 and 2 are related immunoglobulin superfamily cell adhesion proteins required for appropriate synaptic connections between specific subtypes of retinal neurons. Sdks mediate cell-cell adhesion with homophilic specificity that underlies their neuronal targeting function. Here we report crystal structures of Sdk1 and Sdk2 ectodomain regions, revealing similar homodimers mediated by the four N-terminal immunoglobulin domains (Ig1-4), arranged in a horseshoe conformation. These Ig1-4 horseshoes interact in a novel back-to-back orientation in both homodimers through Ig1:Ig2, Ig1:Ig1 and Ig3:Ig4 interactions. Structure-guided mutagenesis results show that this canonical dimer is required for both Sdk-mediated cell aggregation (via trans interactions) and Sdk clustering in isolated cells (via cis interactions). Sdk1/Sdk2 recognition specificity is encoded across Ig1-4, with Ig1-2 conferring the majority of binding affinity and differential specificity. We suggest that competition between cis and trans interactions provides a novel mechanism to sharpen the specificity of cell-cell interactions.

    Organizational Affiliation: 

    Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, United States.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Protein sidekick-2A, B384Mus musculusMutation(s): 0 
Gene Names: Sdk2, Kiaa1514
UniProt
Find proteins for Q6V4S5 (Mus musculus)
Explore Q6V4S5 
Go to UniProtKB:  Q6V4S5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6V4S5
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranoseC, E 3N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G21290RB
GlyCosmos:  G21290RB
GlyGen:  G21290RB
Entity ID: 3
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseD 2N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Experimental Data & Validation

Experimental Data

Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.61α = 90
b = 88.29β = 90
c = 106.56γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
iMOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-09-28
    Type: Initial release
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary