9PHB

CryoEM structure of filament of Bacillus subtilis TIR domain protein SpbK

9PHB の概要

• エントリーDOI: 10.2210/pdb9phb/pdb
• EMDBエントリー: 71644
• 分子名称: SpbK (1 entity in total)
• 機能のキーワード: tir domain protein, antiphage defence, antiviral protein
• 由来する生物種: Bacillus subtilis
• タンパク質・核酸の鎖数: 10
• 化学式量合計: 340755.20

構造登録者

Mishra, B.P.,Ve, T. (登録日: 2025-07-09, 公開日: 2025-12-31, 最終更新日: 2026-01-14)

主引用文献

Mishra, B.P.,Loyo, C.L.,Cai, Y.,Litfin, T.,Miraj, G.,Brillault, L.,Masic, V.,Mosaiab, T.,Rajaratnam, P.,Rudrawar, S.,Gu, W.,Kobe, B.,Gerdt, J.P.,Grossman, A.D.,Shi, Y.,Ve, T.
Molecular characterisation of the Bacillus subtilis SpbK antiphage defence system.
Nat Commun, 2025

PubMed Abstract: Bacteria have a variety of mechanisms for limiting predation by phages. SpbK is a Toll/interleukin-1 receptor (TIR) domain-containing antiphage defence protein from Bacillus subtilis that provides protection against the temperate phage SPβ via abortive infection. Here we structurally characterise SpbK and its interaction with the SPβ protein YonE. We demonstrate that SpbK is an NADase that produces both ADP-ribose (ADPR) and canonical cyclic ADPR with a N1-glycosidic bond (cADPR, also referred to as N1-cADPR). Combining cryo-EM, in silico predictions, site-directed mutagenesis, and phage infection assays, we show that formation of two-stranded head-to-tail assemblies of SpbK TIR domains is required for both NADase activity and antiphage defence. We also demonstrate that YonE is a dodecameric portal protein that activates the NADase function of SpbK by facilitating TIR domain clustering. Collectively, our results provide insight into how bacterial TIR NADases recognise phage infection.

PubMed: 41462020
DOI: 10.1038/s41467-025-67810-5

実験手法

ELECTRON MICROSCOPY (3.3 Å)