An M29 Aminopeptidase from Listeria Monocytogenes Contributes to In Vitro Bacterial Growth but not to Intracellular Infection.

Xian Zhang,Changyong Cheng,Jing Sun,Fengdan Liu,Huifei Yu,Yiran Zhu,Houhui Song,Li Gan,Zhongwei Chen,Yi Hang,Chiyu Guan,Huan Zeng

doi:10.3390/microorganisms8010110

Xian Zhang, Changyong Cheng + Show 10 more

Open Access

https://doi.org/10.3390/microorganisms8010110

Copy DOI

Journal: Microorganisms	Publication Date: Jan 13, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Zhejiang A & F University

Abstract

Aminopeptidases that catalyze the removal of N-terminal residues from polypeptides or proteins are crucial for physiological processes. Here, we explore the biological functions of an M29 family aminopeptidase II from Listeria monocytogenes (LmAmpII). We show that LmAmpII contains a conserved catalytic motif (EEHYHD) that is essential for its enzymatic activity and LmAmpII has a substrate preference for arginine and leucine. Studies on biological roles indicate that LmAmpII is required for in vitro growth in a chemically defined medium for optimal growth of L. monocytogenes but is not required for bacterial intracellular infection in epithelial cells and macrophages, as well as cell-to-cell spreading in fibroblasts. Moreover, LmAmpII is found as dispensable for bacterial pathogenicity in mice. Taken together, we conclude that LmAmpII, an M29 family aminopeptidase, can efficiently hydrolyze a wide range of substrates and is required for in vitro bacterial growth, which lays a foundation for in-depth investigations of aminopeptidases as potential targets to defend Listeria infection.

Highlights

Listeria monocytogenes is a facultative intracellular bacterial pathogen that is capable of passing through the intestinal epithelial barrier, blood-brain barrier, or fetoplacental barrier into target organs and colonizing them, thereby infecting host cells [1,2]
LmAmpII has been predicted as a member of the M29 family [12], but the biological roles of which have not been well characterized to date
We found that LmAmpII is predominantly localized within bacterial cytosol (Figure 1A)

Summary

Introduction

Listeria monocytogenes is a facultative intracellular bacterial pathogen that is capable of passing through the intestinal epithelial barrier, blood-brain barrier, or fetoplacental barrier into target organs and colonizing them, thereby infecting host cells [1,2]. Aminopeptidases (APs), one of the Mpl groups, can catalyze the cleavage of N-terminal amino acids in proteins or peptides, releasing amino acid residues, preferably the hydrophobic residues [5] These peptidases are widely distributed in bacteria, fungi, and other species with important physiological roles, such as protein maturation, protein turnover, hydrolysis of regulatory peptides, nitrogen nutrition, modulation of gene expression, support of the amino acids pool, and virulence factors, and are considered essential enzymes [5,6,7,8,9,10]. We aimed to further elucidate the functional and biochemical characteristics of LmAmpII and the data for the first time to demonstrate the interesting features and biological roles of AmpII in Listeria metabolism and infection. The study supports the potential of this enzyme for applications in biotechnological processes and lays a foundation for in-depth investigations of aminopeptidases as potential targets to defend Listeria infection

Objectives

Methods

Results

Discussion

Conclusion