Characterization of endo-β-N-acetylglucosaminidase from alkaliphilic Bacillus halodurans C-125
Characterization of endo-β-N-acetylglucosaminidase from alkaliphilic Bacillus halodurans C-125
复制标题
DOI：
10.1271/bbb.68.1059
复制
发表时间：
2004-05-01
影响因子：
1.6
通讯作者：
Takegawa, K
中科院分区：
文献类型：
--
作者：
Fujita, K;Takami, H;Takegawa, K
嗜碱芽孢杆菌（Bacillus halodurans）C-125的基因组测序结果表明，该菌株编码一个内切β-N-乙酰氨基葡萄糖苷酶（Endo-BH），其C末端有一个220个氨基酸的尾，C末端有一个634个氨基酸的催化区，与原激素节杆菌（Arthrobacter protophormiae）的内切β-N-乙酰氨基葡萄糖苷酶（Endo-A）有50.1%的同源性。携带Endo-BH基因的转化大肠杆菌细胞表现出内切-β-N-乙酰氨基葡萄糖苷酶活性。重组Endo-BH可水解高甘露糖型寡糖和杂合型寡糖，并具有转糖基活性。在缺失Endo-BH的219个C-末端氨基酸残基时，保留了野生型活性水平，而在缺失Endo-A同源结构域时，蛋白质表达为包涵体，并且这些活性降低。这些结果表明Endo-BH的酶性质与Endo-A的酶性质相似，并且C-末端尾不影响酶活性。虽然C-末端尾区对于酶活性不是必需的，但是该序列在各种来源的内切-β-N-乙酰氨基葡糖苷酶中也是保守的。
The genome sequencing project on alkaliphilic Bacillus halodurans C-125 revealed a putative endo-beta-N-acetylglucosaminidase (Endo-BH), which consists of a signal peptide of 24 amino acids, a catalytic region of 634 amino acids exhibiting 50.1% identity with the endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (Endo-A), and a C-terminal tail of 220 amino acids. Transformed Escherichia coli cells carrying the Endo-BH gene exhibited endo-beta-N-acetylglucosaminidase activity. Recombinant Endo-BH hydrolyzed high-mannose type oligosaccharides and hybrid type oligosaccharides, and showed transglycosylation activity. On deletion of 219 C-terminal amino acid residues of Endo-BH, the wild type level of activity was retained, whereas with deletions of the Endo-A homolog domain, the proteins were expressed as inclusion bodies and these activities were reduced. These results suggest that the enzymatic properties of Endo-BH are similar to those of Endo-A, and that the C-terminal tail does not affect the enzyme activity. Although the C-terminal tail region is not essential for enzyme activity, the sequence is also conserved among endo-beta-N-acetylglucosaminidases of various origins.