title: Gene cloning and characterization of a novel salt-tolerant and glucose-enhanced β-glucosidase from a marine streptomycete.
abstract: The gene BglNH encoding a β-glucosidase was cloned from a marine streptomycete. Sequence analysis revealed that BglNH encoded a 456-aa peptide with a calculated mass of 51 kDa. The deduced amino acid sequence of BglNH showed the highest identities of 61 % with known β-glucosidases and contained a catalytic domain which belonged to the glycoside hydrolase family 1. The gene BglNH was expressed in Escherichia coli and the recombinant enzyme (r-BglNH) was purified. The optimum pH and temperature of r-BglNH were pH6.0 and 45 °C, respectively. The r-BglNH displayed the typical salt-tolerant and glucose-enhanced characteristics. Its activity was remarkably enhanced in the presence of 0.5 M NaCl (rose more than 1.6-fold) and 0.1 M glucose (rose more than 1.4-fold). Moreover, r-BglNH displayed good pH stability and metal tolerance. It remained stable after incubating with buffers from pH4.0 to 10.0, and most metal ions had no significant inhibition on its activity. These properties indicate that r-BglNH is an ideal candidate for further research and industrial applications.
authors: Key Laboratory of Marine Bio-resources Sustainable Utilization CAS, RNAM Center for Marine Microbiology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China.
authors: Zhimao
authors: Z
authors: Mai
authors: Jian
authors: J
authors: Yang
authors: Xinpeng
authors: X
authors: Tian
authors: Jie
authors: J
authors: Li
authors: Si
authors: S
authors: Zhang
mesh_terms: D000192:Actinomycetales / Q000737:chemistry / Q000201:enzymology*; D000595:Amino Acid Sequence; D059001:Aquatic Organisms / Q000737:chemistry / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005947:Glucose / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D055049:Salt Tolerance; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D001617:beta-Glucosidase; D005947:Glucose