Identification of the ZPC Oligosaccharide Ligand Involved in Sperm Binding and the Glycan Structures of Xenopus laevis Vitelline Envelope Glycoproteins1
| Autor: | Jerry L. Hedrick, Loc H. Vo, Ten-Yang Yen, Bruce A. Macher |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
chemistry.chemical_classification
Glycan Glycosylation biology Xenopus Vitelline membrane Cortical granule Cell Biology General Medicine Oligosaccharide Ligand (biochemistry) biology.organism_classification chemistry.chemical_compound Reproductive Medicine chemistry Biochemistry biology.protein Glycoprotein |
| Zdroj: | Biology of Reproduction. 69:1822-1830 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod.103.015370 |
| Popis: | The Xenopus laevis egg vitelline envelope is composed of five glycoproteins (ZPA, ZPB, ZPC, ZPD, and ZPX). As shown previously, ZPC is the primary ligand for sperm binding to the egg envelope, and this binding involves the oligosaccharide moieties of the glycoprotein (Biol. Reprod., 62:766‐774, 2000). To understand the molecular mechanism of sperm-egg envelope binding, we characterized the N-linked glycans of the vitelline envelope (VE) glycoproteins. The N-linked glycans of the VE were composed predominantly of a heterogeneous mixture of highmannose (5-9) and neutral, complex oligosaccharides primarily derived from ZPC (the dominant glycoprotein). However, the ZPA N-linked glycans were composed of acidic-complex and high-mannose oligosaccharides, ZPX had only high-mannose oligosaccharides, and ZPB lacked N-linked oligosaccharides. The consensus sequence for N-linked glycosylation at the evolutionarily conserved residue N113 of the ZPC protein sequence was glycosylated solely with high-mannose oligosaccharides. This conserved glycosylation site may be of importance to the threedimensional structure of the ZPC glycoproteins. One of the complex oligosaccharides of ZPC possessed terminal b-N-acetyl-glucosamine residues. The same ZPC oligosaccharide species isolated from the activated egg envelopes lacked terminal b-Nacetyl-glucosamine residues. We previously showed that the cortical granules contain b-N-acetyl-glucosaminidase (J. Exp. Zool., 235:335‐340, 1985). We propose that an alteration in the oligosaccharide structure of ZPC by glucosaminidase released from the cortical granule reaction is responsible for the loss of sperm binding ligand activity at fertilization. fertilization, gamete biology, ovum, sperm |
| Databáze: | OpenAIRE |
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