Woodward J R, Craik D, Dell A, Khoo K H, Munro S L, Clarke A E, Bacic A
Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia.
Glycobiology. 1992 Jun;2(3):241-50. doi: 10.1093/glycob/2.3.241.
Self-incompatibility in flowering plants of the family Solanaceae is mediated by the product of the S-allele. The allelic products of the S-gene in the female sexual tissues of the pistil are glycoproteins in the mol. wt range 28-32 kDa. These S-glycoproteins have been isolated from styles of Nicotiana alata, homozygous for the S1- and S2-alleles. Earlier studies have indicated that the single potential N-glycosylation site on the S1-glycoprotein bears a glycan chain, whereas of the four potential N-glycosylation sites on the S2-glycoprotein, three are glycosylated. This paper describes the purification and characterization of the N-linked glycan chains from these two glycoproteins. Oligosaccharides were cleaved off the glycoproteins using peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F (N-glycanase F) and separated by anion-exchange HPLC. Four types of hybrid structure were defined by chemical techniques, fast atom bombardment-mass spectrometry (FAB-MS) and 1H-NMR. Although the relative amounts differed, all four structures were found on both the S1- and S2-glycoproteins, and are heterogeneous at some N-glycosylation sites. No O-linked glycans were detected on the S2-glycoprotein. These results are discussed in relation to the potential of the structural diversity residing in this array of glycoforms to play a rôle in allelic specificity.
茄科开花植物中的自交不亲和性由S等位基因的产物介导。雌蕊雌性生殖组织中S基因的等位基因产物是分子量在28 - 32 kDa范围内的糖蛋白。这些S糖蛋白已从S1和S2等位基因纯合的烟草花柱中分离出来。早期研究表明，S1糖蛋白上单一的潜在N - 糖基化位点带有聚糖链，而S2糖蛋白上四个潜在的N - 糖基化位点中有三个被糖基化。本文描述了从这两种糖蛋白中纯化和鉴定N - 连接聚糖链的过程。使用肽 - N4 -（N - 乙酰 - β - 葡糖胺基）天冬酰胺酶F（N - 聚糖酶F）从糖蛋白上切下寡糖，并通过阴离子交换高效液相色谱进行分离。通过化学技术、快原子轰击质谱（FAB - MS）和1H - NMR确定了四种类型的杂合结构。尽管相对含量不同，但在S1和S2糖蛋白上都发现了所有四种结构，并且在一些N - 糖基化位点是异质的。在S2糖蛋白上未检测到O - 连接聚糖。本文结合这种糖型阵列中结构多样性在等位基因特异性中发挥作用的潜力对这些结果进行了讨论。
