Cloning of the Trichoderma reesei cDNA Encoding a Glucuronan Lyase Belonging to a Novel Polysaccharide Lyase Family
Cloning of the Trichoderma reesei cDNA Encoding a Glucuronan Lyase Belonging to a Novel Polysaccharide Lyase Family
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DOI：
10.1128/aem.01749-08
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发表时间：
2009-01-01
影响因子：
4.4
通讯作者：
Isogai, Akira
中科院分区：
文献类型：
--
作者：
Konno, Naotake;Igarashi, Kiyohiko;Isogai, Akira
丝状真菌里氏木霉在以 β-(1 -> 4)-聚葡萄糖醛酸（纤维糖醛酸）作为唯一碳源生长时会产生葡萄糖醛酸裂解酶 (TrGL)。克隆了编码TrGL的cDNA，并在毕赤酵母中异源表达了重组酶。 TrGL的cDNA包括编码20个氨基酸信号肽的777bp开放阅读框和238个氨基酸成熟蛋白。氨基酸序列与先前描述的功能蛋白的氨基酸序列没有相似性，表明该酶应归类于新的多糖裂解酶（PL）家族。重组 TrGL 通过 β-消除作用内切地催化纤维糖醛酸解聚，并且对纤维糖醛酸具有高度特异性。该酶在 pH 6.5 和 50°C 时最活跃，并且其活性和热稳定性在 Ca2+ 存在下增加，表明其钙依赖性与其他 PL（例如果胶酸裂合酶）相似。
The filamentous fungus Trichoderma reesei produces glucuronan lyase (TrGL) when it is grown on beta-(1 -> 4)-polyglucuronate (cellouronate) as a sole carbon source. The cDNA encoding TrGL was cloned, and the recombinant enzyme was heterologously expressed in Pichia pastoris. The cDNA of TrGL includes a 777-bp open reading frame encoding a 20-amino-acid signal peptide and the 238-amino-acid mature protein. The amino acid sequence showed no similarity to the amino acid sequences of previously described functional proteins, indicating that the enzyme should be classified in a novel polysaccharide lyase (PL) family. Recombinant TrGL catalyzed depolymerization of cellouronate endolytically by beta-elimination and was highly specific for cellouronate. The enzyme was most active at pH 6.5 and 50 degrees C, and its activity and thermostability increased in the presence of Ca2+, suggesting that its calcium dependence is similar to that of other PLs, such as pectate lyases.