5B5K
Crystal structure of Izumo1, the mammalian sperm ligand for egg Juno
Summary for 5B5K
| Entry DOI | 10.2210/pdb5b5k/pdb |
| Related | 5EJN |
| Descriptor | Izumo sperm-egg fusion protein 1, 2-acetamido-2-deoxy-beta-D-glucopyranose, 4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID, ... (4 entities in total) |
| Functional Keywords | cell adhesion, fertilization, egg receptor, gamete adhesion, sperm-egg membrane fusion |
| Biological source | Mus musculus (Mouse) |
| Cellular location | Membrane ; Single-pass type I membrane protein : Q9D9J7 |
| Total number of polymer chains | 1 |
| Total formula weight | 27791.83 |
| Authors | Nishimura, K.,Han, L.,De Sanctis, D.,Jovine, L. (deposition date: 2016-05-11, release date: 2016-07-06, Last modification date: 2024-10-23) |
| Primary citation | Nishimura, K.,Han, L.,Bianchi, E.,Wright, G.J.,de Sanctis, D.,Jovine, L. The structure of sperm Izumo1 reveals unexpected similarities with Plasmodium invasion proteins. Curr.Biol., 26:R661-R662, 2016 Cited by 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 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. PubMed: 27374339DOI: 10.1016/j.cub.2016.06.028 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.5 Å) |
Structure validation
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