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Sci Rep. 2015 Nov 27;5:17370. doi: 10.1038/srep17370.

Aminopeptidase T of M29 Family Acts as A Novel Intracellular Virulence Factor for Listeria monocytogenes Infection.

Author information

1
College of Animal Science and Technology, Zhejiang A&F University, 88 Huanchengbei Road, Lin'an, Zhejiang 311300, P. R. China.
2
Zhejiang University Institute of Preventive Veterinary Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, P. R. China.
3
Zhoushan Entry-Exit Inspection and Quarantine Bureau, 555 Haijing Road, Zhoushan, Zhejiang 316000, P. R. China.

Abstract

The foodborne pathogen Listeria monocytogenes employs a number of virulence determinants including metalloproteases to infect hosts. Here for the first time, we identified an M29 family aminopeptidase T (encoded by lmo1603) from L. monocytogenes that possesses a typical feature to catalyze the cleavage of amino acids from peptide substrates, with a preference for arginine. The purified recombinant Lmo1603 was activated by Fe(3+), Zn(2+) and Mn(2+), but strongly stimulated by Co(2+), indicating that Lmo1603 is a cobalt-dependent aminopeptidase. Single mutation at any of the Glu216, Glu281, His308, Tyr315, His327, and Asp329 completely abolished the enzymatic activity of Lmo1603. More importantly, we showed that Lmo1603 was mainly involved in Listeria infection, but not required for growth in rich laboratory medium and minimal defined medium. Disruption of Lmo1603 resulted in almost complete attenuation of Listeria virulence in a mouse infection model. In addition, we demonstrated that Lmo1603 was mainly localized in the bacterial cytosol and required for invasion and survival inside human epithelial cells and murine macrophages. We conclude that Lmo1603 encodes a functional aminopeptidase T of M29 family, which acts as a novel intracellular virulence factor essential in the successful establishment of L. monocytogenes infections in a mouse model.

PMID:
26610705
PMCID:
PMC4661694
DOI:
10.1038/srep17370
[Indexed for MEDLINE]
Free PMC Article

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