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

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...

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Bibliographic Details
Published in细胞研究：英文版 no. 5; pp. 635 - 644
Main Author Peilon Lu Dan Ma Yuling Chen Yingying Guo Guo-Qiang Chen Haiteng Deng Yigong Shi
Format Journal Article
LanguageEnglish
Published 2013
Subjects
L-谷氨酰胺
L-谷氨酸
放氨
游离氨基酸
耐酸性
致病性大肠杆菌
谷氨酰胺酶
酸性环境
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Summary: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.
Bibliography:acid resistance; bacterial stress response; glutaminase; glutamine; amino acid antiporter
31-1568/Q
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.
ISSN:1001-0602
1748-7838