| 大肠杆菌MetJ的基因修饰对其蛋氨酸产量的影响 |
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| 引用本文： | 闫海洋,林松毅,欧阳红生.大肠杆菌MetJ的基因修饰对其蛋氨酸产量的影响[J].现代农业科技,2014(5):296-297,300. |
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| 作者姓名： | 闫海洋 林松毅 欧阳红生 |
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| 作者单位： | 吉林大学军需科技学院;吉林大学动物科技学院; |
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| 摘 要： | 采用1-甲基-3-硝基-1-亚硝基胍基因突变法,得到大肠杆菌K-12的耐蛋氨酸类似物突变体。经过发酵测试,突变菌株获得1 020 mg/L的L-蛋氨酸产量。研究结果表明:L-蛋氨酸生物合成过程中的2个关键酶,即胱硫醚γ-合酶与胱硫醚β-裂解酶,在L-蛋氨酸发酵过程中未受到蛋氨酸的反馈阻遏。采用PCR方法对突变体的MetJ蛋白克隆并进行基因测序可知,野生型的第54位的丝氨酸基因被替换为天冬氨酰,使得反馈阻遏作用消除,从而有效提高L-蛋氨酸的发酵产量。
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| 关 键 词： | 大肠杆菌 蛋氨酸阻遏蛋白 反馈阻遏 基因修饰 L-蛋氨酸产量 |
Effect of Gene Modification in Escherichia coli MetJ on Its L-met Production |
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| Institution: | YAN Hai-yang,LIN Song-yi,OUYANG Hong-sheng (1 Quartermaster College, Jilin University, Changehun Jilin 130062 ; 2.College of Animal Sciences, Jilin University) |
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| Abstract: | Gene mutation was carried out using N-methyl-N′-nitro-N-nitrosoguanidine. L-met-analogue-resistant mutants were derived from Escherichia coli K-12. The mutants produced 1 020 mg/L L-met in the fermentation test. It was confirmed that two key enzymes ,cystathionine γ-synthase and cystathionineβ-lyase were not repressed by excess of L-met during fermentation. MetJ protein was cloned and sequenced by the PCR. It was observed that serine at position 54 was replaced by asparaginate ,which enhanced L-met production because of the depression of L-met biosynthetic enzymes. |
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| Keywords: | Escherichia coli MetJ feedback repression gene modification L-met production |
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