1. Peptide Occurring in Enterobacteriaceae Triggers Streptococcus pneumoniae Cell Death.
- Author
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Nasher F, Kwun MJ, Croucher NJ, Heller M, and Hathaway LJ
- Subjects
- Bacterial Proteins genetics, Bacterial Proteins metabolism, Carrier Proteins genetics, Carrier Proteins metabolism, Caspases metabolism, Gene Expression Profiling, Lipoproteins genetics, Lipoproteins metabolism, Microscopy, Electron, N-Acetylmuramoyl-L-alanine Amidase metabolism, Protein Binding, Proteome analysis, Streptococcus pneumoniae genetics, Streptococcus pneumoniae ultrastructure, Anti-Infective Agents pharmacology, Enterobacteriaceae metabolism, Microbial Viability drug effects, Peptides pharmacology, Ribosomal Proteins pharmacology, Streptococcus pneumoniae drug effects
- Abstract
Non-encapsulated S treptococcus pneumoniae often possess two genes, aliB- like ORF 1 and aliB- like ORF 2, in place of capsule genes. AliB -like ORF 1 is thought to encode a substrate binding protein of an ABC transporter which binds peptide SETTFGRDFN, found in 50S ribosomal subunit protein L4 of Enterobacteriaceae. Here, we investigated the effect of binding of AliB-like ORF 1 peptide on the transcriptome and proteome of non-encapsulated pneumococci. We found upregulation of gene expression of a metacaspase and a gene encoding N-acetylmuramoyl-L-alanine amidase, both of which are proposed to be involved in programmed cell death in prokaryotic cells. Proteome profiling indicated upregulation of transcriptional regulators and downregulation of metabolism-associated genes. Exposure to the peptide specifically triggered death in pneumococci which express AliB-like ORF 1, with the bacteria having an apoptotic appearance by electron microscopy. We propose that binding of the AliB-like ORF 1 peptide ligand by the pneumococcus signals a challenging environment with hostile bacterial species leading to death of a proportion of the pneumococcal population.
- Published
- 2019
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