Arabinosylation Plays a Crucial Role in Extensin Cross-linking In Vitro.
Arabinosylation Plays a Crucial Role in Extensin Cross-linking In Vitro.
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DOI：
10.4137/bci.s31353
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发表时间：
2015
影响因子：
--
通讯作者：
Kieliszewski MJ
中科院分区：
文献类型：
--
作者：
Chen Y;Dong W;Tan L;Held MA;Kieliszewski MJ
伸展蛋白（Extensins，EXTs）是一种富含羟脯氨酸的糖蛋白（hydroxyproline-rich glycoproteins，HRGPs），是植物初生细胞壁的结构成分。它们是碱性蛋白质，并且高度糖基化，其中碳水化合物占其干重的>50%。碳水化合物以单半乳糖基丝氨酸和阿拉伯糖基羟脯氨酸的形式存在，阿拉伯糖苷的大小范围为约1至4或5个残基。拟定的EXT阿拉伯糖基化功能包括稳定聚脯氨酸II螺旋结构和促进EXT交联。在这里，通过使用体外交联测定法测定部分或完全去阿拉伯糖基化的EXT的初始交联速率和交联度，然后通过凝胶渗透色谱法研究了EXT交联中阿拉伯糖基化的参与。我们的研究结果表明，EXT的体外交联需要EXT的阿拉伯糖基化和四阿拉伯糖侧链中的第四个阿拉伯糖基残基，这是唯一的α-连接，可以决定初始交联速率。我们的研究结果也证实了保守的结构的oligoarabinosides跨物种，表明进化意义的EXT阿拉伯糖基化。
Extensins (EXTs) are hydroxyproline-rich glycoproteins (HRGPs) that are structural components of the plant primary cell wall. They are basic proteins and are highly glycosylated with carbohydrate accounting for >50% of their dry weight. Carbohydrate occurs as monogalactosyl serine and arabinosyl hydroxyproline, with arabinosides ranging in size from ~1 to 4 or 5 residues. Proposed functions of EXT arabinosylation include stabilizing the polyproline II helix structure and facilitating EXT cross-linking. Here, the involvement of arabinosylation in EXT cross-linking was investigated by assaying the initial cross-linking rate and degree of cross-linking of partially or fully de-arabinosylated EXTs using an in vitro cross-linking assay followed by gel permeation chromatography. Our results indicate that EXT arabinosylation is required for EXT cross-linking in vitro and the fourth arabinosyl residue in the tetraarabinoside chain, which is uniquely α-linked, may determine the initial cross-linking rate. Our results also confirm the conserved structure of the oligoarabinosides across species, indicating an evolutionary significance for EXT arabinosylation.