Chiu P C N, Tsang H Y, Koistinen R, Koistinen H, Seppala M, Lee K F, Yeung W S B
Department of Obstetrics and Gynaecology, University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
Biol Reprod. 2004 Jun;70(6):1710-9. doi: 10.1095/biolreprod.103.023259. Epub 2004 Feb 18.
Previous data showed that glycodelin-A from amniotic fluid and glycodelin-F from follicular fluid inhibited sperm-zona pellucida binding. Solubilized zona pellucida reduced the binding of glycodelin-F to sperm extract dose dependently. This study demonstrated that the zona pellucida proteins also reduced the binding of glycodelin-A to sperm extract. Ionophore-induced acrosome reaction reduced the binding of iodinated glycodelin-A and -F to sperm, indicating that the glycodelin-binding sites are on the outer acrosomal membrane or on the sperm plasma membrane overlying the acrosome. While the binding of glycodelin-A to sperm was suppressed by mannose and fucose neoglycoproteins, that of glycodelin-F was also reduced by acetylglucosamine neoglycoprotein. Pretreatment of sperm with inhibitors of mannosidase and acetylglucosaminidase reduced the binding of glycodelin-F to sperm. On the other hand, inhibitor of mannosidase but not of acetylglucosaminidase inhibited the binding of glycodelin-A. In a competition binding assay, mannosidase reduced both glycodelin-A and -F binding whereas acetylglucosaminidase reduced only glycodelin-F binding. While fucosidase reduced the binding of both glycodelins, fucosidase inhibitor was marginally active in suppressing the binding of glycodelins to human sperm. Among the selectins tested, only E-selectin had a slight inhibitory effect on the binding of glycodelin-A to sperm. The binding of glycodelin-F was unaffected by selectins and their antibodies. In conclusion, the binding of glycodelin-A to sperm involves mannose, fucose, and possibly E- selectin residues, while that of glycodelin-F involves mannose, fucose, and N-acetylglucosamine but not the selectin residue.
先前的数据表明，羊水来源的糖蛋白A和卵泡液来源的糖蛋白F可抑制精子与透明带的结合。可溶性透明带能剂量依赖性地降低糖蛋白F与精子提取物的结合。本研究表明，透明带蛋白也能降低糖蛋白A与精子提取物的结合。离子载体诱导的顶体反应降低了碘化糖蛋白A和F与精子的结合，表明糖蛋白结合位点位于顶体外膜或覆盖顶体的精子质膜上。虽然甘露糖和岩藻糖新糖蛋白可抑制糖蛋白A与精子的结合，但乙酰葡糖胺新糖蛋白也可降低糖蛋白F与精子的结合。用甘露糖苷酶和N-乙酰葡糖胺糖苷酶抑制剂预处理精子可降低糖蛋白F与精子的结合。另一方面，甘露糖苷酶抑制剂而非N-乙酰葡糖胺糖苷酶抑制剂可抑制糖蛋白A的结合。在竞争结合试验中，甘露糖苷酶可降低糖蛋白A和F的结合，而N-乙酰葡糖胺糖苷酶仅降低糖蛋白F的结合。虽然岩藻糖苷酶可降低两种糖蛋白的结合，但岩藻糖苷酶抑制剂在抑制糖蛋白与人类精子结合方面活性微弱。在所测试的选择素中，只有E-选择素对糖蛋白A与精子的结合有轻微抑制作用。糖蛋白F的结合不受选择素及其抗体的影响。总之，糖蛋白A与精子的结合涉及甘露糖、岩藻糖，可能还有E-选择素残基，而糖蛋白F与精子的结合涉及甘露糖、岩藻糖和N-乙酰葡糖胺，但不涉及选择素残基。
