3NK4: Crystal structure of full-length sperm receptor ZP3 at 2.0 A resolution

Citation:
Abstract
ZP3, 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.
PDB ID: 3NK4Download
MMDB ID: 86112
PDB Deposition Date: 2010/6/18
Updated in MMDB: 2010/11
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 3NK4: tetrameric; determined by author and by software (PISA)
Molecular Components in 3NK4
Label Count Molecule
Proteins (4 molecules)
2
Zona Pellucida 3(Gene symbol: ZP3)
Molecule annotation
2
Zona Pellucida 3(Gene symbol: ZP3)
Molecule annotation
Chemicals (3 molecules)
1
1
2
2
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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