| Title |
Cel8H, a Novel Endoglucanase from the Halophilic Bacterium Halomonas sp. S66-4: Molecular Cloning, Heterogonous Expression, and Biochemical Characterization |
| Author |
Xiaoluo Huang1, Zongze Shao2, Yuzhi Hong3, Ling Lin1, Chanjuan Li1, Fei Huang1, Hui Wang1, and Ziduo Liu1* |
| Address |
1State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P. R. China, 2Key Laboratory of Marine Biogenetic Resources, The Third Institute of Oceanography, State of Oceanic Administration, Xiamen 361005, P. R. China, 3College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, P. R. China |
| Bibliography |
Journal of Microbiology, 48(3),318-324, 2010,
|
| DOI |
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| Key Words |
endoglucanase, salt tolerance, pH stability, temperature stability, Halomonas sp. |
| Abstract |
A recombinant Escherichia coli clone expressing an endoglucanase was identified from a genomic library of the halophilic bacterium Halomonas sp. S66-4, and the enzyme was designated Cel8H. The cel8H gene consisted of 1,053 bp and encoded 350 amino acids sharing the highest identity of 48% to other known endoglucanases. The protein was expressed in E. coli BL21 (DE3) and purified to homogeneity. The purified recombinant enzyme had an optimal activity of 4.9 U/mg at pH 5 and 45°C toward the substrate carboxymethylcellulose. It exhibited extraordinary properties which differed from endoglucanases reported previously at the point of high salt tolerance above 5 M, simultaneously with high pH stability at pH 4-12 and high temperature stability at 40-60°C. Various substrate tests indicated that the enzyme hydrolyzes β-1,4-glucosidic bonds specifically. |
