Animal Nutrition Division, National Institute of Animal Nutrition and Physiology, Bangalore, Karnataka, India.
Appl Biochem Biotechnol. 2012 May;167(1):132-41. doi: 10.1007/s12010-012-9660-5. Epub 2012 Apr 20.
The metagenomic approach has been used successfully to isolate novel biocatalyst gene from uncultured microorganisms. The gene encoding exo-1,4-β-glucanase avicelase was amplified from the metagenome of the Equus burchelli fecal sample and cloned. The gene was found to be of 1,007 bp of nucleotide which encodes a protein of 318 amino acids with a calculated MW of 36 kDa. The deduced amino acid sequence was homologous with cellulases belonging to the glycosyl hydrolases 6 superfamily. The expressed protein was active towards the substrates avicel and carboxymethyl cellulose, indicating that it has bifunctional cellulolytic enzyme activity. The recombinant protein showed an activity of 5.23 U with specific activity of 6.8 U mg(-1) protein with the substrate avicel, while when CMC was used, an activity of 3.0 U with a specific activity of 4.2 U mg(-1) protein was achieved. Its optimum pH was determined to be 7.0 and optimum temperature of 35°C.
元基因组方法已成功用于从未培养的微生物中分离新型生物催化剂基因。从非洲野驴粪便样本的元基因组中扩增并克隆了编码外切-1,4-β-葡聚糖酶纤维二糖酶的基因。该基因长 1007 个核苷酸，编码 318 个氨基酸的蛋白质，计算分子量为 36 kDa。推导的氨基酸序列与属于糖苷水解酶 6 超家族的纤维素酶同源。表达的蛋白质对底物微晶纤维素和羧甲基纤维素具有活性，表明它具有双功能纤维素酶活性。重组蛋白在以微晶纤维素为底物时的活性为 5.23 U，比活为 6.8 U mg(-1) 蛋白，而当使用 CMC 时，活性为 3.0 U，比活为 4.2 U mg(-1) 蛋白。其最适 pH 值为 7.0，最适温度为 35°C。
