3nk3 | pdb_00003nk3
Crystal structure of full-length sperm receptor ZP3 at 2.6 A resolution
Structural highlights
FunctionZP3_CHICK Component of the zona pellucida, which mediates species-specific sperm binding. Directly binds to sperm. Important for egg fertilization.[1] [2] Publication Abstract from PubMedZP3, a major component of the zona pellucida (ZP) matrix coating mammalian eggs, is essential for fertilization by acting as sperm receptor. By retaining a propeptide that contains a polymerization-blocking external hydrophobic patch (EHP), we determined the crystal structure of an avian homolog of ZP3 at 2.0 A resolution. The structure unveils the fold of a complete ZP domain module in a homodimeric arrangement required for secretion and reveals how EHP prevents premature incorporation of ZP3 into the ZP. This suggests mechanisms underlying polymerization and how local structural differences, reflected by alternative disulfide patterns, control the specificity of ZP subunit interaction. Close relative positioning of a conserved O-glycan important for sperm binding and the hypervariable, positively selected C-terminal region of ZP3 suggests a concerted role in the regulation of species-restricted gamete recognition. Alternative conformations of the area around the O-glycan indicate how sperm binding could trigger downstream events via intramolecular signaling. Insights into egg coat assembly and egg-sperm interaction from the X-ray structure of full-length ZP3.,Han L, Monne M, Okumura H, Schwend T, Cherry AL, Flot D, Matsuda T, Jovine L Cell. 2010 Oct 29;143(3):404-15. Epub 2010 Oct 21. PMID:20970175[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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