L_-glutamine provides acid resistance for Escherichia coil through enzymatic release of ammonia  

作　　者：Peilon Lu Dan Ma Yuling Chen Yingying Guo Guo-Qiang Chen Haiteng Deng Yigong Shi 

机构地区：[1]Ministry of Education Key Laboratory of Protein Science, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China [2]Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China [3]Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua Uni- versity, Beijing 100084, China [4]Ministry of Education Key Laboratory of Bioinformatics, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China

出　　处：《Cell Research》2013年第5期635-644,共10页细胞研究（英文版）

摘　　要：Bacteria, exemplified by enteropathogenic Escherichia coli （E. coh）, rely on elaborate acid resistance systems to survive acidic environment （such as the stomach）. Comprehensive understanding of bacterial acid resistance is important for prevention and clinical treatment. In this study, we report a previously uncharacterized type of acid resis tance system in E. coli that relies on L-glutamine （Gin）, one of the most abundant food-borne free amino acids. Upon uptake into E. coli, Gin is converted to L-glutamate （Glu） by the acid-activated glutaminase YbaS, with concomitant release of gaseous ammonia. The free ammonia neutralizes proton, resulting in elevated intracellular pH under acidic environment. We show that YbaS and the amino acid antiporter GadC, which exchanges extracellular Gin with intracellular Glu, together constitute an acid resistance system that is sufficient for E. coli survival under extremely acidic environment.

关 键 词：acid resistance bacterial stress response GLUTAMINASE GLUTAMINE amino acid antiporter 

分 类 号：TQ464.7[化学工程—制药化工] S858.285.1[农业科学—临床兽医学]