白色念珠菌CYP51蛋白功能性氨基酸残基定点突变、蛋白表达及活性测定

实验设计了白色念珠菌CYP51蛋白功能性氨基酸残基突变体Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R, 并转入基因工程菌D12667中表达。用Western及紫外分光光度法定性、定量检测蛋白, 用GC-MS法测定蛋白代谢活性。结果表明, 成功表达目标蛋白, 蛋白诱导表达量接近微粒体蛋白总量的25%。活性测定表明, 表达的野生型蛋白保持其对天然底物的代谢能力; 相较于野生型蛋白, 突变体蛋白代谢活性不同程度改变, 最多可下降1/2左右。因此, 本研究中成功表达了野生型和

Expression and Detection the Enzyme Activity of the Wild and Mutation Type of CYP51 Protein of Candida albicans

The Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R　mutants of Candida albicans sterol 14α-demethylase (CACYP51) were constructed and heterologously expressed in D12667, the recon-structed strain with the deletion of CYP51 gene of the Y12667. With the strains obtained and microsome enzymes separated, the western blot and the ultraviolet absorption spectrophotometry were used to qualita-tive and quantitative detect the expressed protein, the GC-MS was used to detect the metabolism activity of the protein. The results showed that, the target protein expressed successfully in the reconstructed strains, with the expression level up to 25% of the total microsome proteins. The results also showed that, the wild type protein had the catalytic activity to its nature substrate. While after alteration the wild gene with Y118A、Y118F、Y118T、S378A、S378T、H310A、H31 OR by a single base substitution, the catalytic activity of protein markedly decreased respectively. So the wild type and mutation CYP51 were expressed success-fully in Saccharomyces cerevisiae and the expression products preserved the activity to metabolism their nature substrate.