Reappraisal of the DNA phosphorothioate modification machinery : uncovering neglected functional modalities and identification of new counter-invader defense systems

© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research..

The DndABCDE systems catalysing the unusual phosphorothioate (PT) DNA backbone modification, and the DndFGH systems, which restrict invasive DNA, have enigmatic and paradoxical features. Using comparative genomics and sequence-structure analyses, we show that the DndABCDE module is commonly functionally decoupled from the DndFGH module. However, the modification gene-neighborhoods encode other nucleases, potentially acting as the actual restriction components or suicide effectors limiting propagation of the selfish elements. The modification module's core consists of a coevolving gene-pair encoding the DNA-scanning apparatus - a DndD/CxC-clade ABC ATPase and DndE with two ribbon-helix-helix (MetJ/Arc) DNA-binding domains. Diversification of DndE's DNA-binding interface suggests a multiplicity of target specificities. Additionally, many systems feature DNA cytosine methylase genes instead of PT modification, indicating the DndDE core can recruit other nucleobase modifications. We show that DndFGH is a distinct counter-invader system with several previously uncharacterized domains, including a nucleotide kinase. These likely trigger its restriction endonuclease domain in response to multiple stimuli, like nucleotides, while blocking protective modifications by invader methylases. Remarkably, different DndH variants contain a HerA/FtsK ATPase domain acquired from multiple sources, including cellular genome-segregation systems and mobile elements. Thus, we uncovered novel HerA/FtsK-dependent defense systems that might intercept invasive DNA during replication, conjugation, or packaging.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:52

Enthalten in:

Nucleic acids research - 52(2024), 3 vom: 09. Feb., Seite 1005-1026

Sprache:

Englisch

Beteiligte Personen:

Rakesh, Siuli [VerfasserIn]
Aravind, L [VerfasserIn]
Krishnan, Arunkumar [VerfasserIn]

Links:

Volltext

Themen:

9007-49-2
Adenosine Triphosphatases
DNA
DNA Restriction-Modification Enzymes
EC 3.6.1.-
Journal Article

Anmerkungen:

Date Completed 15.02.2024

Date Revised 15.02.2024

published: Print

Citation Status MEDLINE

doi:

10.1093/nar/gkad1213

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36654277X