本文選題：α-L-鼠李糖苷酶　切入點：基因密碼子　出處：《蠶業(yè)科學》2017年04期 　論文類型：期刊論文

【摘要】：桑樹富含黃酮苷類化合物,利用糖苷酶生物轉(zhuǎn)化可有效提高其生物利用度,對挖掘桑樹資源的藥食用價值具有重要意義。天然來源的糖苷酶催化選擇性強,但異源表達量低。以源自黑曲霉(Aspergillus niger)的α-L-鼠李糖苷酶基因rha為目的基因,改善該基因的密碼子偏愛性和適應性,將密碼子優(yōu)化后的corha基因展示表達到釀酒酵母細胞表面,以達到高效催化的實用目的。與轉(zhuǎn)入原始rha基因的重組釀酒酵母菌株相比,轉(zhuǎn)入密碼子優(yōu)化corha基因的重組釀酒酵母菌株表面展示coRHA蛋白的表達量提高了2.9倍,培養(yǎng)60 h后coRHA的酶活力提高了2.7倍。以對硝基苯-α-L-鼠李糖苷(p NPR)為底物檢測含corha基因重組菌株生產(chǎn)coRHA的酶活力,其最適p H及溫度分別為5.0和45℃;以蘆丁為底物,在p H 5.0、60℃條件下,coRHA水解蘆丁合成異槲皮苷的得率為79.81%±3.1%。采用系統(tǒng)密碼子優(yōu)化策略,為利用工程菌工業(yè)化生產(chǎn)coRHA,用于催化桑樹黃酮苷類化合物定向水解提供了可行的方法。
[Abstract]:Mulberry is rich in flavonoid glycosides. The bioconversion of glycosidase can effectively improve the bioavailability of mulberry, which is of great significance for exploiting the edible value of mulberry resources. The 偽 -L- rhamnosidase gene (rha) from Aspergillus Niger was used as the target gene to improve the codon preference and adaptability of the gene. The optimized corha gene was expressed on the surface of Saccharomyces cerevisiae cells. Compared with the recombinant Saccharomyces cerevisiae strain with the original rha gene, the expression of coRHA protein on the surface of the recombinant Saccharomyces cerevisiae strain with codon optimized corha gene was increased 2.9 times. The enzyme activity of coRHA was increased by 2.7 times after 60 h culture. The enzyme activity of the recombinant strain containing corha gene was detected by using p-nitrobenzen- 偽 -rhamnoside as substrate. The optimum pH and temperature were 5.0 and 45 鈩，

本文編號：1622989