Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 beta-glucosidase.
Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 beta-glucosidase.
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水稻糖基水解酶家族1和OS4BGLU12β-葡萄糖苷酶的表达分析。
DOI：
10.1186/1471-2229-6-33
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发表时间：
2006-12-29
影响因子：
5.3
通讯作者：
Cairns, James R. Ketudat
中科院分区：
文献类型：
--
作者：
Opassiri, Rodjana;Pomthong, Busarakum;Onkoksoong, Tassanee;Akiyama, Takashi;Esen, Asim;Cairns, James R. Ketudat
葡萄糖基水解酶家族1（GH 1）β-葡萄糖苷酶参与了植物的重要生理过程，如对生物和非生物胁迫的应答、对植食动物的防御、植物激素的激活、木质化和细胞壁重塑等。植物GH 1 β-葡萄糖苷酶是由多基因家族编码的，因此我们预测了这些基因的结构和蛋白产物的性质，并研究了它们与其它植物GH 1成员的亲缘关系、表达和活性，从而开始研究它们在水稻中的作用。在水稻数据库中共鉴定出40个GH 1基因，包括2个可能的内生菌基因、2个可能的假基因、2个基因片段和34个明显感受态的糖苷酶基因。系统发育分析表明，具有密切相关序列的GH 1成员具有相似的基因结构，并且通常聚集在同一染色体上。大多数基因似乎来自水稻和拟南芥谱系从其共同祖先分化后发生的重复，这两种植物只有8个共同的基因谱系。根据公开数据库中的cDNA和EST序列，至少有31个GH 1基因在水稻的一系列器官和阶段中表达。Os 4 bglu 12基因的cDNA通过RT-PCR从水稻幼苗中分离，Os 4 bglu 12基因编码与先前从发芽水稻中纯化的细胞壁结合酶的N-末端序列在44个氨基酸残基中的40个相同的蛋白质。在大肠杆菌中表达的硫氧还蛋白-Os 4 bglu 12融合蛋白能有效水解β-（1，4）-连接的3-6个葡萄糖残基的寡糖和海带二糖。对数据库序列的仔细分析产生了更可靠的水稻GH 1基因结构和蛋白质产物预测。由于这些基因中的大多数是在水稻和拟南芥的祖先分化之后分化的，因此只有少数基因的功能可以从拟南芥和其他双子叶植物的GH 1酶中得到暗示。这意味着分析单子叶植物中的GH 1酶对于了解它们在主要粮食作物中的功能是必要的。为了开始该分析，对Os 4 bglu 12 β-葡糖苷酶进行表征，发现其具有高的外切葡聚糖酶活性，这与其在细胞壁代谢中的作用一致。
Glycosyl hydrolase family 1 (GH1) β-glucosidases have been implicated in physiologically important processes in plants, such as response to biotic and abiotic stresses, defense against herbivores, activation of phytohormones, lignification, and cell wall remodeling. Plant GH1 β-glucosidases are encoded by a multigene family, so we predicted the structures of the genes and the properties of their protein products, and characterized their phylogenetic relationship to other plant GH1 members, their expression and the activity of one of them, to begin to decipher their roles in rice. Forty GH1 genes could be identified in rice databases, including 2 possible endophyte genes, 2 likely pseudogenes, 2 gene fragments, and 34 apparently competent rice glycosidase genes. Phylogenetic analysis revealed that GH1 members with closely related sequences have similar gene structures and are often clustered together on the same chromosome. Most of the genes appear to have been derived from duplications that occurred after the divergence of rice and Arabidopsis thaliana lineages from their common ancestor, and the two plants share only 8 common gene lineages. At least 31 GH1 genes are expressed in a range of organs and stages of rice, based on the cDNA and EST sequences in public databases. The cDNA of the Os4bglu12 gene, which encodes a protein identical at 40 of 44 amino acid residues with the N-terminal sequence of a cell wall-bound enzyme previously purified from germinating rice, was isolated by RT-PCR from rice seedlings. A thioredoxin-Os4bglu12 fusion protein expressed in Escherichia coli efficiently hydrolyzed β-(1,4)-linked oligosaccharides of 3–6 glucose residues and laminaribiose. Careful analysis of the database sequences produced more reliable rice GH1 gene structure and protein product predictions. Since most of these genes diverged after the divergence of the ancestors of rice and Arabidopsis thaliana, only a few of their functions could be implied from those of GH1 enzymes from Arabidopsis and other dicots. This implies that analysis of GH1 enzymes in monocots is necessary to understand their function in the major grain crops. To begin this analysis, Os4bglu12 β-glucosidase was characterized and found to have high exoglucanase activity, consistent with a role in cell wall metabolism.
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影响因子：
5.2
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