黑曲霉糖化酶基因上游调控区的克隆与分析

目的:通过基因工程方法改造糖化酶基因上游调控区,提高糖化酶产量提供研究。方法:以糖化酶生产菌黑曲霉为材料,通过PCR扩增获得糖化酶基因上游调控区片段PglaA。经测序比对发现该序列与GenBank中编号AM270061的序列相似性为100%。进一步的分析结果表明此序列含有2个保守的激活蛋白结合位点序列CCAAT和1个可能的葡萄糖阻遏位点CT-GGGG。结果:通过不同浓度葡萄糖对糖化酶合成的影响确定该菌株存在葡萄糖阻遏效应,当浓度到到3%以上时阻遏率高达70%以上,为葡萄糖阻遏位点预测结果提供了实验证据,并且经实验测得糖化酶活力随着接种量的增加而增加,当增加到5%时,相对酶活最高。

Cloning and Analysis of Aspergillus niger Glucoamylase Gene Upstream Regulatory Region

Objective:Provided new ideas for modifying glucoamylase gene upstream regulatory region by genetic engineering and improving the expression of glucoamylase.Method:Glucoamylase production by Aspergillus niger as the material,cloned regulatory PglaA upstream glucoamylase gene by PCR.The similarity of comparing PglaA with sequence which was numbered AM270061 in the GenBank was 100%.The analysis showed that the PglaA contains two conserved binding sites of activator protein and a possible site of glucose repression.Result:The impact of glucose with different concentrations on glucoamylase determined the existence of the repressor effect of strain which provides experimental evidence.When the concentration to more than 3 percent,the repression had 70 percent,increased to 5%,the highest activity.