Presence of asparagine-linked N-acetylglucosamine and chitobiose in Pyrus pyrifolia S-RNases associated with gametophytic self-incompatibility
Presence of asparagine-linked N-acetylglucosamine and chitobiose in Pyrus pyrifolia S-RNases associated with gametophytic self-incompatibility
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DOI：
10.1046/j.1432-1327.1999.00499.x
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发表时间：
1999-08-01
期刊：
影响因子：
--
通讯作者：
Norioka, S
中科院分区：
文献类型：
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作者：
Ishimizu, T;Mitsukami, Y;Norioka, S
在配子体自交不亲和反应中，由蔷薇科和茄科植物的S基因座编码的S-核糖核酸酶区分花粉的S等位基因，但如何区分尚不清楚。本文报道了蔷薇科梨属植物中七种S核糖核酸酶N-糖基化位点上的N-糖链的结构。通过对S-4-核糖核酸酶制备的吡啶氨基糖链的色谱分析和对还原的和S羧甲基化的S-核糖核酸酶的酶解产物的液相色谱/电喷雾电离-质谱分析，鉴定了其结构。S-4-核糖核酸酶携带各种类型的糖链，包括植物特有的含有β1-->；2连接的木糖和α1-->；3连接的岩藻糖残基的糖链。然而，S-4-核糖酶的N-糖链中有70%以上是N-乙酰氨基葡萄糖或壳二糖(GlcNAc beta 1-->；4GlcNAc)，这在自然界中是不存在的。N-乙酰氨基葡萄糖和壳二糖主要存在于S核糖核酸酶可能识别位点的N-糖基化位点，提示这些糖链可能与花粉S产物(S)相互作用。
S-RNases encoded by the S-locus of rosaceous and solanaceous plants discriminate between the S-alleles of pollen in gametophytic self-incompatibility reactions, but it is not clear how. We report the structures of N-glycans attached to each of the N-glycosylation sites of seven S-RNases in Pyr us pyrifolia of the Rosaceae. The structures were identified by chromatographic analysis of pyridyiaminnted sugar chains prepared from S-4-RNase and by liquid chromatography/electrospray ionization-mass spectrometric analysis of the protease digests of reduced and S-carboxymethylated S-RNases. S-4-RNase carries various types of sugar chains, including plant-specific ones with beta 1-->2-linked xylose and alpha 1-->3-linked fucose residues. More than 70% of the total N-glycans of S-4-RNase are, however, an N-acetylglucosamine or a chitobiose (GlcNAc beta 1-->4GlcNAc), which has not been found naturally. The N-acetylglucosamine and chitobiose are mainly present at the N-glycosylation sites within the putative recognition sites of the S-RNase, suggesting that these sugar chains may interact with pollen S-product(s).