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Listeria monocytogenes aguA1, but not aguA2, encodes a functional agmatine deiminase: biochemical characterization of its catalytic properties and roles in acid tolerance.

ABSTRACT: Listeria monocytogenes is adaptable to low pH environments and therefore crosses the intestinal barrier to establish systemic infections. L. monocytogenes aguA1 and aguA2 encode putative agmatine deiminases (AgDIs) AguA1 and AguA2. Transcription of aguA1 and aguA2 was significantly induced at pH 5.0. Deletion of aguA1 significantly impaired its survival both in gastric fluid at pH 2.5 and in mouse stomach, whereas aguA2 deletion did not show significant defect of survival in gastric fluid. With agmatine as the sole substrate, AguA1 expressed in Escherichia coli was optimal at 25 °C and over a wide range of pH from 3.5 to 10.5. Recombinant AguA2 showed no deiminase activity. Site-directed mutagenesis revealed that all nine AguA1 mutants completely lost enzymatic activity. AguA2 acquired AgDI activity only when Cys-157 was mutated to glycine. AguA1 mutation at the same site, G157C, also inactivated the enzyme. Thus, we have discovered Gly-157 as a novel residue other than the known catalytic triad (Cys-His-Glu/Asp) in L. monocytogenes that is critical for enzyme activity. Of the two putative AgDIs, we conclude that only AguA1 functionally participates in the AgDI pathway and mediates acid tolerance in L. monocytogenes.

SUBMITTER: Cheng C

PROVIDER: S-EPMC3772207 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature

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Listeria monocytogenes aguA1, but not aguA2, encodes a functional agmatine deiminase: biochemical characterization of its catalytic properties and roles in acid tolerance.

Cheng Changyong C Chen Jianshun J Fang Chun C Xia Ye Y Shan Ying Y Liu Yuan Y Wen Guilan G Song Houhui H Fang Weihuan W

The Journal of biological chemistry 20130805 37

Listeria monocytogenes is adaptable to low pH environments and therefore crosses the intestinal barrier to establish systemic infections. L. monocytogenes aguA1 and aguA2 encode putative agmatine deiminases (AgDIs) AguA1 and AguA2. Transcription of aguA1 and aguA2 was significantly induced at pH 5.0. Deletion of aguA1 significantly impaired its survival both in gastric fluid at pH 2.5 and in mouse stomach, whereas aguA2 deletion did not show significant defect of survival in gastric fluid. With ...[more]

PMID: 23918931

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Dataset Information

Listeria monocytogenes aguA1, but not aguA2, encodes a functional agmatine deiminase: biochemical characterization of its catalytic properties and roles in acid tolerance.

Publications

Listeria monocytogenes aguA1, but not aguA2, encodes a functional agmatine deiminase: biochemical characterization of its catalytic properties and roles in acid tolerance.

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