Target ssDNA activates the NADase activity of prokaryotic SPARTA immune system

© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc..

Argonaute proteins (Agos), which use small RNAs or DNAs as guides to recognize complementary nucleic acid targets, mediate RNA silencing in eukaryotes. In prokaryotes, Agos are involved in immunity: the short prokaryotic Ago/TIR-APAZ (SPARTA) immune system triggers cell death by degrading NAD+ in response to invading plasmids, but its molecular mechanisms remain unknown. Here we used cryo-electron microscopy to determine the structures of inactive monomeric and active tetrameric Crenotalea thermophila SPARTA complexes, revealing mechanisms underlying SPARTA assembly, RNA-guided recognition of target single-stranded DNA (ssDNA) and subsequent SPARTA tetramerization, as well as tetramerization-dependent NADase activation. The small RNA guides Ago to recognize its ssDNA target, inducing SPARTA tetramerization via both Ago- and TIR-mediated interactions and resulting in a two-stranded, parallel, head-to-tail TIR rearrangement primed for NAD+ hydrolysis. Our findings thus identify the molecular basis for target ssDNA-mediated SPARTA activation, which will facilitate the development of SPARTA-based biotechnological tools.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:20

Enthalten in:

Nature chemical biology - 20(2024), 4 vom: 07. Apr., Seite 503-511

Sprache:

Englisch

Beteiligte Personen:

Zhang, Jun-Tao [VerfasserIn]
Wei, Xin-Yang [VerfasserIn]
Cui, Ning [VerfasserIn]
Tian, Ruilin [VerfasserIn]
Jia, Ning [VerfasserIn]

Links:

Volltext

Themen:

0U46U6E8UK
63231-63-0
DNA, Single-Stranded
EC 3.2.2.5
Journal Article
NAD
NAD+ Nucleosidase
RNA

Anmerkungen:

Date Completed 29.03.2024

Date Revised 03.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1038/s41589-023-01479-z

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM364243376