A lysozyme with altered substrate specificity facilitates prey cell exit by the periplasmic predator Bdellovibrio bacteriovorus

Harding, Christopher J.; Huwiler, Simona G.; Somers, Hannah; Lambert, Carey; Ray, Luke J.; Till, Rob; Taylor, Georgina; Moynihan, Patrick J.; Sockett, R. Elizabeth; Lovering, Andrew L.

Abstract

Lysozymes are among the best-characterized enzymes, acting upon the cell wall substrate peptidoglycan. Here, examining the invasive bacterial periplasmic predator Bdellovibrio bacteriovorus, we report a diversified lysozyme, DslA, which acts, unusually, upon (GlcNAc-) deacetylated peptidoglycan. B. bacteriovorus are known to deacetylate the peptidoglycan of the prey bacterium, generating an important chemical difference between prey and self walls and implying usage of a putative deacetyl-specific “exit enzyme”. DslA performs this role, and ΔDslA strains exhibit a delay in leaving from prey. The structure of DslA reveals a modified lysozyme superfamily fold, with several adaptations. Biochemical assays confirm DslA specificity for deacetylated cell wall, and usage of two glutamate residues for catalysis. Exogenous DslA, added ex vivo, is able to prematurely liberate B. bacteriovorus from prey, part-way through the predatory lifecycle. We define a mechanism for specificity that invokes steric selection, and use the resultant motif to identify wider DslA homologues.

Citation

Harding, C. J., Huwiler, S. G., Somers, H., Lambert, C., Ray, L. J., Till, R., Taylor, G., Moynihan, P. J., Sockett, R. E., & Lovering, A. L. (2020). A lysozyme with altered substrate specificity facilitates prey cell exit by the periplasmic predator Bdellovibrio bacteriovorus. Nature Communications, 11, Article 4817. https://doi.org/10.1038/s41467-020-18139-8

• Journal Article Type: Article
• Acceptance Date: Aug 6, 2020
• Online Publication Date: Sep 23, 2020
• Publication Date: Sep 23, 2020
• Deposit Date: Oct 6, 2020
• Publicly Available Date: Oct 6, 2020
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Article Number: 4817
• DOI: https://doi.org/10.1038/s41467-020-18139-8
• Keywords: General Biochemistry, Genetics and Molecular Biology; General Physics and Astronomy; General Chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/4928733
• Publisher URL: https://www.nature.com/articles/s41467-020-18139-8