Functional characterization of the N-Acetylmuramyl-ι-Alanine Amidase, Ami1, from Mycobacterium abscessus

Tanja Küssau, Niël Van Wyk, Matt D. Johansen, Husam M. A. B. Alsarraf, Aymeric Neyret, Claire Hamela, Kasper K. Sørensen, Mikkel B. Thygesen, Claire Beauvineau, Laurent Kremer, Mickaël Blaise*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Peptidoglycan (PG) is made of a polymer of disaccharides organized as a three-dimensional mesh-like network connected together by peptidic cross-links. PG is a dynamic structure that is essential for resistance to environmental stressors. Remodeling of PG occurs throughout the bacterial life cycle, particularly during bacterial division and separation into daughter cells. Numerous autolysins with various substrate specificities participate in PG remodeling. Expression of these enzymes must be tightly regulated, as an excess of hydrolytic activity can be detrimental for the bacteria. In non-tuberculous mycobacteria such as Mycobacterium abscessus, the function of PG-modifying enzymes has been poorly investigated. In this study, we characterized the function of the PG amidase, Ami1 from M. abscessus. An ami1 deletion mutant was generated and the phenotypes of the mutant were evaluated with respect to susceptibility to antibiotics and virulence in human macrophages and zebrafish. The capacity of purified Ami1 to hydrolyze muramyl-dipeptide was demonstrated in vitro. In addition, the screening of a 9200 compounds library led to the selection of three compounds inhibiting Ami1 in vitro. We also report the structural characterization of Ami1 which, combined with in silico docking studies, allows us to propose a mode of action for these inhibitors.

Original languageEnglish
Article number2410
Number of pages25
JournalCells
Volume9
Issue number11
DOIs
Publication statusPublished - Nov 2020
Externally publishedYes

Bibliographical note

Copyright the Author(s) 2020. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • drug screening
  • Mycobacterium abscessus
  • N-acetylmuramyl-l-alanine amidase
  • peptidoglycan
  • x-ray crystallography

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