Ashiuchi M, Soda K, Misono H
Research Institute of Molecular Genetics, Kochi University, Nankoku, Kochi, 783-8502, Japan.
Biochem Biophys Res Commun. 1999 Sep 16;263(1):6-12. doi: 10.1006/bbrc.1999.1298.
Three genes encoding a poly-gamma-glutamate synthetic system of Bacillus subtilis IFO 3336 (Bacillus natto) were cloned and expressed in Escherichia coli. The E. coli clone produced poly-gamma-glutamate extracellularly. The genes, newly designated as pgsBCA, were homologous with capBCA genes of Bacillus anthracis. All of pgsB, pgsC, and pgsA genes were essential for the polymer production. Addition of Mn(2+), instead of Mg(2+), to the polymer-synthesis medium resulted in an increase in the polymer yield. Co-expression of glutamate racemase gene in E. coli cells harboring pgsBCA genes increased both the polymer production and D-glutamate content in the polymer. The polymer produced by the E. coli clone was higher in average molecular size than that produced by B. subtilis IFO 3336.
编码枯草芽孢杆菌IFO 3336（纳豆芽孢杆菌）聚γ-谷氨酸合成系统的三个基因被克隆并在大肠杆菌中表达。该大肠杆菌克隆在细胞外产生聚γ-谷氨酸。这些基因，新命名为pgsBCA，与炭疽芽孢杆菌的capBCA基因同源。pgsB、pgsC和pgsA基因对于聚合物的产生都是必需的。在聚合物合成培养基中添加Mn(2+)而非Mg(2+)会导致聚合物产量增加。在含有pgsBCA基因的大肠杆菌细胞中共表达谷氨酸消旋酶基因会增加聚合物产量以及聚合物中D-谷氨酸的含量。该大肠杆菌克隆产生的聚合物平均分子大小比枯草芽孢杆菌IFO 3336产生的聚合物更大。
