Microheterogeneity of N-glycosylation on a stylar self-incompatibility glycoprotein of Nicotiana alata.
Microheterogeneity of N-glycosylation on a stylar self-incompatibility glycoprotein of Nicotiana alata.
复制标题
烟草花柱自交不亲和性糖蛋白 N-糖基化的微观异质性。
DOI：
10.1093/glycob/5.5.517
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发表时间：
1995
期刊：
影响因子：
4.3
通讯作者：
A. Bacic
中科院分区：
文献类型：
--
作者：
D. Oxley;A. Bacic
配子体自交不亲和性是有花植物中防止近亲繁殖的一种机制，它是由一个单一的遗传位点S-位点的产物介导的。烟草（Nicotiana阿拉塔）雌性生殖组织中的S基因产物是一系列具有核糖核酸酶活性的糖蛋白。在这项研究中，我们报告的N-连接的糖基化在四个潜在的N-糖基化位点的S2-糖蛋白的微观异质性。阿拉塔的S-糖蛋白含有1 - 5个基于共有序列Asn-Xaa-Ser/Thr的潜在N-糖基化位点。S2-糖蛋白在Asn 27、Asn 37、Asn 38和Asn 150处含有四个潜在的N-糖基化位点，分别命名为位点I、II、IV和V。位点III不存在于S2-糖蛋白中。由胰蛋白酶和胰凝乳蛋白酶digestrase从S2-糖蛋白产生的糖肽的分析揭示了聚糖的类型和存在于每个站点的微观异质性的程度。位点I（Asn 27）和IV（Asn 138）显示出微异质性，位点II（Asn 37）仅含有单一类型的N-聚糖，位点V（Asn 150）未糖基化。在S2-糖蛋白的位点I观察到的微观异质性与在S1-糖蛋白的唯一位点，位点I观察到的微观异质性相同（Woodward et al.，Glycobiology，2，241-250，1992）。由于在站点I的N-糖基化的共识序列是保守的所有S-糖蛋白从其他物种的自交不亲和茄科植物，在这个网站的糖基化可能是重要的，他们的功能。在S2-糖蛋白上未检测到其他翻译后修饰（例如O-糖基化、磷酸化）。
Gametophytic self-incompatibility, a mechanism that prevents inbreeding in some families of flowering plants, is mediated by the products of a single genetic locus, the S-locus. The products of the S-gene in the female sexual tissues of Nicotiana alata are an allelic series of glycoproteins with RNase activity. In this study, we report on the microheterogeneity of N-linked glycosylation at the four potential N-glycosylation sites of the S2-glycoprotein. The S-glycoproteins from N.alata contain from one to five potential N-glycosylation sites based on the consensus sequence Asn-Xaa-Ser/Thr. The S2-glycoprotein contains four potential N-glycosylation sites at Asn27, Asn37, Asn38 and Asn 150, designated sites I, II, IV and V, respectively. Site III is absent from the S2-glycoprotein. Analysis of glycopeptides generated from the S2-glycoprotein by trypsin and chymotrypsin digestions revealed the types of glycans and the degree of microheterogeneity present at each site. Sites I (Asn27) and IV (Asn138) display microheterogeneity, site II (Asn37) contains only a single type of N-glycan, and site V (Asn150) is not glycosylated. The microheterogeneity observed at site I on the S2-glycoprotein is the same as that observed at the only site, site I, on the S1-glycoprotein (Woodward et al., Glycobiology, 2, 241-250, 1992). Since the N-glycosylation consensus sequence at site I is conserved in all S-glycoproteins from other species of self-incompatible solanaceous plants, glycosylation at this site may be important to their function. No other post-translational modifications (e.g. O-glycosylation, phosphorylation) were detected on the S2-glycoprotein.