Cloning and characterization of a thermostable intracellular α-amylase gene from the hyperthermophilic bacterium Thermotoga maritima MSB8
Cloning and characterization of a thermostable intracellular α-amylase gene from the hyperthermophilic bacterium Thermotoga maritima MSB8
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DOI：
10.1016/j.resmic.2003.09.005
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发表时间：
2003-12-01
影响因子：
2.6
通讯作者：
Yun, HD
中科院分区：
文献类型：
--
作者：
Lim, WJ;Park, SR;Yun, HD
从极端嗜热菌海栖热袍菌（Thermotoga maritima）MSB 8中克隆了编码胞内α-淀粉酶AmyB（TM 1650）的基因，并在大肠杆菌中表达。AmyB酶水解α-1，4淀粉键。amyB基因全长1269 bp，编码422个氨基酸（计算分子量为50 ~ 187 Da）。经淀粉非变性聚丙烯酰胺凝胶电泳（SDS-PAGE）测得该酶的分子量为50 000 Da。AmyB的氨基酸序列与其他淀粉酶的同源性小于12%，但含有4个在α-淀粉酶中高度保守的区域。AmyB α-淀粉酶在pH 7.0时具有最大酶活性，最适活性温度为70 ℃。与许多其它生物的α-淀粉酶一样，海栖热霉MSB 8 α-淀粉酶、在E.在Ca ~（2+）（10 μ M）存在下，对大肠杆菌的作用增强。(C)2003年，Elsevier SAS。All rights reserved.
The gene encoding an intracellular alpha-amylase, AmyB (TM 1650), from Thermotoga maritima MSB8, a hyperthermophilic bacterium, was cloned and expressed in Escherichia coli. The AmyB enzyme hydrolyzed alpha-1,4 starch linkage. The amyB gene is 1269 bp in length, encoding a protein of 422 amino acids (calculated molecular mass of 50 187 Da). The molecular weight of the enzyme was estimated to be 50 000 Da by SDS-PAGE after starch-nondenaturing-PAGE. The amino acid sequence of AmyB showed less than 12% identity to other amylases, but contained four regions that are highly conserved among alpha-amylases. The AmyB alpha-amylase exhibited maximal enzymatic activity at pH 7.0 and its optimum temperature for activity was 70degreesC. Like the alpha-amylases of many other organisms, the thermostability of T maritima MSB8 alpha-amylase, AmyB expressed in E. coli was enhanced in the presence of Ca2+ (10 MM). (C) 2003 Elsevier SAS. All rights reserved.