Biochemical and molecular characterization of a putative endoglucanase in Magnaporthegrisea
Biochemical and molecular characterization of a putative endoglucanase in Magnaporthegrisea
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DOI：
10.1007/s00294-008-0179-9
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发表时间：
2008-02
期刊：
影响因子：
2.5
通讯作者：
Jie Zhou;Xiang-zi Zheng;Lan Lan-Lan;Cheng-zeng Lin;Yubing Wu;Xiong-jie Lin;D. Ebbole;Guo-dong Lu;Zonghua Wang
中科院分区：
文献类型：
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作者：
Jie Zhou;Xiang-zi Zheng;Lan Lan-Lan;Cheng-zeng Lin;Yubing Wu;Xiong-jie Lin;D. Ebbole;Guo-dong Lu;Zonghua Wang
微生物病原体分泌一系列细胞壁降解酶来破坏宿主细胞壁的结构，以促进宿主组织的定殖。为了更好地了解它们在发病机制中的作用，本文对稻瘟菌中一种推定的内切葡聚糖酶进行了表征。SignalP-3.0分析表明，MGG_02532.5inM.稻瘟病菌（命名为MgEGL 1，用于M. grisea内切葡聚糖酶1）含有分泌信号肽。多重序列比对表明MgEGL 1与构巢曲霉和里氏木霉的内切葡聚糖酶（EC 3.1.1.4）具有高度同源性。这三种蛋白都有一个保守的催化结构域，但只有T.酵母含有纤维素结合模块，MgEGL 1在菌丝体中组成型表达最高，在分生孢子中表达最低。有趣的是，MgEGL 1 RNA在体外培养和感染水稻后可以交替加工。表达分析证实MgEGL 1是一种分泌蛋白。采用刚果红平板法测定了该菌株的内切葡聚糖酶活性，并进一步用二硝基水杨酸法进行了验证。本文的研究结果为进一步确定该内切葡聚糖酶蛋白的生化特性及其在真菌致病中的相关功能奠定了基础。
Microbial pathogens secrete an array of cell wall-degrading enzymes to break down the structure of the host cell wall to facilitate colonization of the host tissue. To better understand their role in the pathogenesis, a putative endoglucanase fromMagnaporthe grisea wascharacterized in this paper. SignalP-3.0 analysis indicates that the protein encoded by geneMGG_02532.5inM. grisea(named MgEGL1 forM.griseaendoglucanase1) contains a secretory signal peptide. Multiple alignment shows that MgEGL1 has high level of homology to endoglucanases (EC 3.1.1.4) fromAspergillus nidulansandTrichoderma reesei. The three proteins share a conserved catalytic domain, but only the one fromT. reeseicontains a cellulose binding module.MgEGL1was constitutively expressed with the highest level in mycelia and the lowest in conidia. Interestingly, theMgEGL1RNA could be alternatively processed when cultured in vitro and after infection of rice. Expression analysis confirmed that the MgEGL1 is a secreted protein. Its endoglucanase activity was assayed by Congo red plates, and further confirmed by the dinitrosalicylic acid method. The finding in this paper will provide the basis for further determination of the biochemical properties of the endoglucanase protein and its relevant function in fungal pathogenesis.