Bacillus methylotrophicus γ-聚谷氨酸合成酶基因的克隆表达

Cloning and Expression of Poly-γ-Glutamic Acid Synthase Gene of Bacillus methylotrophicus

研究了一株非谷氨酸依赖型γ-聚谷氨酸(poly-γ-glutamic acid,γ-PGA)产生菌Bacillus methylotrophicus SK19.001合成酶基因在大肠杆菌中的克隆和表达。以p ET-28a(+)载体构建含有pgs BCA合成酶基因的表达载体,转化至大肠杆菌Escherichia coli BL21构建重组菌。结果表明,在分别以葡萄糖和谷氨酸为底物的培养基中,重组工程菌都具有合成γ-PGA的能力,说明pgs BCA合成酶基因对于B.methylotrophicus SK19.001产γ-PGA是必需的。pgs BCA合成酶基因序列比对的结果的表明,pgs B和pgs C基因编码的氨基酸序列相对保守。

The poly-γ-glutamic acid（γ-PGA） synthase gene pgsBCA of a glutamic acid-independent γ-PGA producing strain Bacillus methylotrophicus SK19.001 was cloned and expressed in the Escherichia coli. The pET-28a-pgs vector harboring pgsBCA genes were constructed and transformed into E.coli BL21. E. coli BL21 could synthesize γ-PGA when cultivated in the flask culture of LB plus glucose and L-glutamate,respectively. The pgsBCA genes were proved be essential for the synthesis of γ-PGA in B. methylotrophicus SK19.001. The blast result of deduced amino acid sequence from the pgsBCA genes in SK19.001 comparing other reported strains showed that the pgsB and pgsC gene were relatively conservative gene for pgsBCA.