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Toxic anti-phage defense proteins inhibited by intragenic antitoxin proteins

Recombination-promoting nuclease (Rpn) proteins are broadly distributed across bacterial phyla, yet their functions remain unclear. Here we report these proteins are new toxin-antitoxin systems, comprised of genes-within-genes, that combat phage infection. We show the small, highly variable Rpn C-te...

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Detalles Bibliográficos
Autores principales: Zhong, Aoshu, Jiang, Xiaofang, Hickman, Alison B., Klier, Katherine, Teodoro, Gabriella I. C., Dyda, Fred, Laub, Michael T., Storz, Gisela
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10327210/
https://www.ncbi.nlm.nih.gov/pubmed/37425788
http://dx.doi.org/10.1101/2023.05.02.539157
Descripción
Sumario:Recombination-promoting nuclease (Rpn) proteins are broadly distributed across bacterial phyla, yet their functions remain unclear. Here we report these proteins are new toxin-antitoxin systems, comprised of genes-within-genes, that combat phage infection. We show the small, highly variable Rpn C-terminal domains (Rpn(S)), which are translated separately from the full-length proteins (Rpn(L)), directly block the activities of the toxic full-length proteins. The crystal structure of RpnA(S) revealed a dimerization interface encompassing a helix that can have four amino acid repeats whose number varies widely among strains of the same species. Consistent with strong selection for the variation, we document plasmid-encoded RpnP2(L) protects Escherichia coli against certain phages. We propose many more intragenic-encoded proteins that serve regulatory roles remain to be discovered in all organisms.