Cloning and Characterizing the Thermophilic and Detergent Stable Cellulase CelMytB from Saccharophagus sp. Myt-1.
Cloning and Characterizing the Thermophilic and Detergent Stable Cellulase CelMytB from Saccharophagus sp. Myt-1.
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从食糖菌属 (Saccharophagus sp.) 中克隆和表征耐热且对洗涤剂稳定的纤维素酶 CelMytB。
DOI：
10.1007/s12088-013-0421-0
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
S.
中科院分区：
文献类型：
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作者：
Sakatoku;A.;Tanaka;D.;Kamachi;H.;and Nakamura;S.
我们以前分离并报道了第二种食蚜蝇属，食蚜蝇属。菌株Myt-1。在本研究中，纤维素酶基因（celMytB）从基因组DNA的Myt-1的克隆和表征。该DNA序列片段含有1，893 bp的开放阅读框，编码631个氨基酸的蛋白质，估计分子量为66.8 kDa。CelMytB蛋白具有一个催化结构域，该结构域包含糖基水解酶家族5的保守特征序列（VIYEIYNEPL）和一个CBM 6纤维素结合模块。CelMytB在55 °C和pH 6.5下显示出最佳活性，这与来自密切相关的S.降解物2 -40。然而，CelMytB的纤维素酶（可溶性纤维素的降解）和微晶纤维素酶（结晶纤维素的降解）活性分别比cel 5 H的等效活性高约3倍和100倍。CelMytB对木聚糖有一定的降解作用。根据酶谱结果，我们推测CelMytB的催化结构域即使没有纤维素结合模块也具有高活性。一些洗涤剂的存在刺激CelMytB的纤维素酶活性。
We previously isolated and reported a second species of theSaccharophagusgenus,Saccharophagussp. strain Myt-1. In the present study, a cellulase gene (celMytB) from the genomic DNA of Myt-1 was cloned and characterized. The DNA sequence fragment contained an open reading frame of 1,893 bp that encoded a protein of 631 amino acids with an estimated molecular mass of 66.8 kDa. The deduced protein, CelMytB, had a catalytic domain that contained a conserved signature sequence (VIYEIYNEPL) of glycosyl hydrolase family 5 and a CBM6 cellulose binding module. CelMytB showed optimal activity at 55 °C and pH 6.5, which is similar to the optimal temperature and pH profile of cel5H, an endoglucanase from the closely relatedS. degradans2-40. However, the cellulase (degradation of soluble cellulose) and avicelase (degradation of crystalline cellulose) activities of CelMytB were about 3-fold and 100-fold higher, respectively, than the equivalent activities of cel5H. Moreover, CelMytB could degrade xylan. From the zymogram results, we speculated that the catalytic domain of CelMytB had high activity even without the cellulose binding module. The presence of some detergents stimulated the cellulase activity of CelMytB.