5jke | pdb_00005jke
Crystal structure of human IZUMO1-JUNO complex (crystal form 3)
Structural highlights
Function[IZUM1_HUMAN] Essential sperm cell-surface protein required for fertilization by acting as a ligand for IZUMO1R/JUNO receptor on egg. The IZUMO1:IZUMO1R/JUNO interaction is a necessary adhesion event between sperm and egg that is required for fertilization but is not sufficient for cell fusion. The ligand-receptor interaction probably does not act as a membrane 'fusogen'.[1] [JUNO_HUMAN] Receptor for IZUMO1 present at the cell surface of oocytes (oolemma), which is essential for species-specific gamete recognition and fertilization. The IZUMO1:IZUMO1R/JUNO interaction is a necessary adhesion event between sperm and egg that is required for fertilization but is not sufficient for cell fusion. The ligand-receptor interaction probably does not act as a membrane 'fusogen'. Does not bind folate.[UniProtKB:Q9EQF4] Publication Abstract from PubMedFertilization is a fundamental process in sexual reproduction, creating a new individual through the combination of male and female gametes. The IZUMO1 sperm membrane protein and its counterpart oocyte receptor JUNO have been identified as essential factors for sperm-oocyte interaction and fusion. However, the mechanism underlying their specific recognition remains poorly defined. Here, we show the crystal structures of human IZUMO1, JUNO and the IZUMO1-JUNO complex, establishing the structural basis for the IZUMO1-JUNO-mediated sperm-oocyte interaction. IZUMO1 exhibits an elongated rod-shaped structure comprised of a helical bundle IZUMO domain and an immunoglobulin-like domain that are each firmly anchored to an intervening beta-hairpin region through conserved disulfide bonds. The central beta-hairpin region of IZUMO1 provides the main platform for JUNO binding, while the surface located behind the putative JUNO ligand binding pocket is involved in IZUMO1 binding. Structure-based mutagenesis analysis confirms the biological importance of the IZUMO1-JUNO interaction. This structure provides a major step towards elucidating an essential phase of fertilization and it will contribute to the development of new therapeutic interventions for fertility, such as contraceptive agents. Structure of IZUMO1-JUNO reveals sperm-oocyte recognition during mammalian fertilization.,Ohto U, Ishida H, Krayukhina E, Uchiyama S, Inoue N, Shimizu T Nature. 2016 Jun 15;534(7608):566-9. doi: 10.1038/nature18596. PMID:27309808[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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