5B5K

Crystal structure of Izumo1, the mammalian sperm ligand for egg Juno

  • Classification: CELL ADHESION
  • Organism(s): Mus musculus
  • Expression System: Homo sapiens

  • Deposited: 2016-05-11 Released: 2016-07-06 
  • Deposition Author(s): Nishimura, K., Han, L., De Sanctis, D., Jovine, L.
  • Funding Organization(s): Karolinska Institutet; Swedish Research Council; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine; Sven and Ebba-Christina Hagberg foundation; EMBO Young Investigator; European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) 

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.257 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The structure of sperm Izumo1 reveals unexpected similarities with Plasmodium invasion proteins.

Nishimura, K.Han, L.Bianchi, E.Wright, G.J.de Sanctis, D.Jovine, L.

(2016) Curr.Biol. 26: R661-R662

  • DOI: 10.1016/j.cub.2016.06.028

  • PubMed Abstract: 
  • Fertilization, the culminating event in sexual reproduction, occurs when haploid sperm and egg recognize each other and fuse to form a diploid zygote. In mammals this process critically depends on the interaction between Izumo1, a protein exposed on ...

    Fertilization, the culminating event in sexual reproduction, occurs when haploid sperm and egg recognize each other and fuse to form a diploid zygote. In mammals this process critically depends on the interaction between Izumo1, a protein exposed on the equatorial segment of acrosome-reacted sperm, and the egg plasma-membrane-anchored receptor Juno [1,2]. The molecular mechanism triggering gamete fusion is unresolved because both Izumo1 and Juno lack sequence similarity to known membrane fusogens. Here we report the crystal structure of Izumo1, which reveals a membrane distal region composed of a four-helix bundle connected to a carboxy-terminal immunoglobulin (Ig)-like domain through a β-hairpin stabilized by disulfide bonds. Remarkably, different regions of Izumo1 display significant structural similarities to two proteins expressed by the invasive sporozoite stage of Plasmodium parasites: SPECT1, which is essential for host cell traversal and hepatocyte invasion [3]; and TRAP, which is necessary for gliding motility and invasion [4]. These observations suggest a link between the molecular mechanisms underlying host cell invasion by the malaria parasite and gamete membrane fusion at fertilization.


    Related Citations: 
    • The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs.
      Inoue, N.,Ikawa, M.,Isotani, A.,Okabe, M.
      (2005) Nature 434: 234
    • Juno is the egg Izumo receptor and is essential for mammalian fertilization.
      Bianchi, E.,Doe, B.,Goulding, D.,Wright, G.J.
      (2014) Nature 508: 483
    • Divergent evolution of vitamin B9 binding underlies Juno-mediated adhesion of mammalian gametes.
      Han, L.,Nishimura, K.,Sadat Al Hosseini, H.,Bianchi, E.,Wright, G.J.,Jovine, L.
      (2016) Curr. Biol. 26: R100


    Organizational Affiliation

    Department of Biosciences and Nutrition & Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Izumo sperm-egg fusion protein 1
A
236Mus musculusMutation(s): 0 
Gene Names: Izumo1
Find proteins for Q9D9J7 (Mus musculus)
Go to UniProtKB:  Q9D9J7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EPE
Query on EPE

Download SDF File 
Download CCD File 
A
4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
HEPES
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.257 
  • Space Group: I 4 2 2
Unit Cell:
Length (Å)Angle (°)
a = 103.280α = 90.00
b = 103.280β = 90.00
c = 139.270γ = 90.00
Software Package:
Software NamePurpose
XDSdata scaling
XDSdata reduction
PHENIXrefinement
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Karolinska InstitutetSweden--
Swedish Research CouncilSweden2012-5093
Goran Gustafsson Foundation for Research in Natural Sciences and MedicineSweden--
Sven and Ebba-Christina Hagberg foundationSweden--
EMBO Young Investigator--
European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)ERC 260759

Revision History 

  • Version 1.0: 2016-07-06
    Type: Initial release
  • Version 1.1: 2016-08-03
    Type: Database references