【摘要】 对与萜烯类香气前体及与抗病虫害有密切关系的茶树(Camellia sinensis)β-葡萄糖苷酶cDNA进行克隆和原核表达。结果表明,该酶cDNA全长序列为1 475 bp(GenBank登录号为AF537127),与其它植物同源性为40％～60％。α-螺旋构象14.33％、β-折叠构象25.43％,存在多个氨基酸功能结构域。利用pET-32a表达载体构建的重组质粒,转化到大肠杆菌(Escherichia coil)菌株BL21zztrxB(DE3)中,诱导产生63 kD的融合蛋白,表达产物具有正常的生物学活性,能催化葡萄糖苷键的水解反应;诱导表达结果显示,主要在细胞质中以可溶性蛋白形式进行表达。更多还原

【Abstract】 The β-glucosidase gene has important effects on the alcoholic aroma precursors and insect-resistance. The complete cDNA squence of β-glucosidase of tea (Camellia sinensis) was cloned and its full length was 1475 bp (GenBank, Accession No. AF537127), and shared 40%～60% similarity to corresponding parts of β-glucosidase gene from other plants in nucleotide sequence. Its secondary structure contained 14.33% α-helical conformation, 25.43% β-sheet conformation and many function domains of amino acid. The β-glucosidase gene was cloned into the pET-32a expression vector and expressed high-efficiently in Escherichia coil BL21 (DE3), and the molecular weight of expressed fusion protein was 63 kD. The results of emzymatic reaction showed that fusion protein possesed normal bioactivity, and it could catalyze the dehydration of the glycodic bond. The fusion protein was mainly expressed by soluble protein in cytoplasm.更多还原