CLONING, EXPRESSION AND CHARACTERIZATION OF Pro3 GENE OF YEAST Saccharomyces cerevisiae

The proline biosynthetic pathway and Pro genes in Saccharomyces cerevisiae have just begun to be studied recently. In our laboratory, Pro2 gene of S. cerevisiae had been cloned in yeast. As described in this paper, yeast Pro3 gene was also cloned, which can complement yeast Pro3 mutants, and be expressed efficiently in E. coli. The high activities of this gene product, L-pyrroline-5-carboxylate (P5C) reductase, can be detected in both organisms. The activity of the Pro3 gene product in multiple copy plasmids is not higher than that of single copy genes in chromosomes in both yeast and E. coll. The preliminary characterization of the gene is also reported.     

啤酒酵母PRO3基因的克隆、表达及鉴定

酵母菌的脯氨酸合成代谢途径及其酶基因的研究是近几年才开始的。我们曾在细菌中克隆了酵母的PRO2基因。在此基础上,我们又进一步克隆了PRO3基因。它不仅能在酵母中很好互补,也能在细菌中高效表达,并且都能测到很高的酶活力,说明了此基因在真核酵母菌和原核细菌中都能利用它们的转录,翻译等系统。当PRO3基因克隆到多拷贝质粒上后,不论在酵母中,还是在细菌中,其基因产物的活性并不比在单拷贝染色体上的活性高。说明此基因的表达在调节上有着它的特殊性。