5K6W

Sidekick-1 immunoglobulin domains 1-5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.50 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

wwPDB Validation 3D Report Full Report



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: 10.7554/eLife.19058
  • Structures With Same Primary Citation

  • 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 underlie ...

    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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Protein sidekick-1
A, B
481Mus musculusMutation(s): 0 
Gene Names: Sdk1
Find proteins for Q3UH53 (Mus musculus)
Go to UniProtKB:  Q3UH53
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download CCD File 
A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
FUC
Query on FUC

Download CCD File 
A, B
ALPHA-L-FUCOSE
C6 H12 O5
SHZGCJCMOBCMKK-SXUWKVJYSA-N
 Ligand Interaction
SO4
Query on SO4

Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download CCD File 
A, B
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.50 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 21
  • Diffraction Data DOI: 10.15785/SBGRID/369 SBGrid
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.14α = 90
b = 152.87β = 90
c = 158.97γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
iMOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2016-09-28
    Type: Initial release