7TH0

Escherichia coli RpnA-S

Summary for 7TH0

• Entry DOI: 10.2210/pdb7th0/pdb
• Descriptor: Recombination-promoting nuclease RpnA (2 entities in total)
• Functional Keywords: toxin-antitoxin phage defense endonuclease abortive infection, antitoxin
• Biological source: Escherichia coli str. K-12 substr. MG1655
• Total number of polymer chains: 1
• Total formula weight: 5517.86

Authors

Zhong, A.,Hickman, A.B.,Storz, G.,Dyda, F. (deposition date: 2022-01-10, release date: 2023-03-29, Last modification date: 2024-11-13)

Primary citation

Zhong, A.,Jiang, X.,Hickman, A.B.,Klier, K.,Teodoro, G.I.C.,Dyda, F.,Laub, M.T.,Storz, G.
Toxic antiphage defense proteins inhibited by intragenic antitoxin proteins.
Proc.Natl.Acad.Sci.USA, 120:e2307382120-e2307382120, 2023

PubMed Abstract: Recombination-promoting nuclease (Rpn) proteins are broadly distributed across bacterial phyla, yet their functions remain unclear. Here, we report that these proteins are toxin-antitoxin systems, comprised of genes-within-genes, that combat phage infection. We show the small, highly variable Rpn -terminal domains (Rpn), which are translated separately from the full-length proteins (Rpn), directly block the activities of the toxic Rpn. The crystal structure of RpnA revealed a dimerization interface encompassing α 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 that plasmid-encoded RpnP2 protects against certain phages. We propose that many more intragenic-encoded proteins that serve regulatory roles remain to be discovered in all organisms.

PubMed: 37487082
DOI: 10.1073/pnas.2307382120

Experimental method

X-RAY DIFFRACTION (1.9 Å)