3RQ9

Structure of Tsi2, a Tse2-immunity protein from Pseudomonas aeruginosa

3RQ9 の概要

• エントリーDOI: 10.2210/pdb3rq9/pdb
• 分子名称: Type VI secretion immunity protein (2 entities in total)
• 機能のキーワード: immunity protein, type vi secretion, t6s, antitoxin, tse2-binding protein
• 由来する生物種: Pseudomonas aeruginosa
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 19191.25

構造登録者

Li, M.,Le Trong, I.,Stenkamp, R.E.,Mougous, J.D. (登録日: 2011-04-27, 公開日: 2012-03-21, 最終更新日: 2024-02-28)

主引用文献

Li, M.,Le Trong, I.,Carl, M.A.,Larson, E.T.,Chou, S.,De Leon, J.A.,Dove, S.L.,Stenkamp, R.E.,Mougous, J.D.
Structural Basis for Type VI Secretion Effector Recognition by a Cognate Immunity Protein.
Plos Pathog., 8:e1002613-e1002613, 2012

PubMed Abstract: The type VI secretion system (T6SS) has emerged as an important mediator of interbacterial interactions. A T6SS from Pseudomonas aeruginosa targets at least three effector proteins, type VI secretion exported 1-3 (Tse1-3), to recipient Gram-negative cells. The Tse2 protein is a cytoplasmic effector that acts as a potent inhibitor of target cell proliferation, thus providing a pronounced fitness advantage for P. aeruginosa donor cells. P. aeruginosa utilizes a dedicated immunity protein, type VI secretion immunity 2 (Tsi2), to protect against endogenous and intercellularly-transferred Tse2. Here we show that Tse2 delivered by the T6SS efficiently induces quiescence, not death, within recipient cells. We demonstrate that despite direct interaction of Tsi2 and Tse2 in the cytoplasm, Tsi2 is dispensable for targeting the toxin to the secretory apparatus. To gain insights into the molecular basis of Tse2 immunity, we solved the 1.00 Å X-ray crystal structure of Tsi2. The structure shows that Tsi2 assembles as a dimer that does not resemble previously characterized immunity or antitoxin proteins. A genetic screen for Tsi2 mutants deficient in Tse2 interaction revealed an acidic patch distal to the Tsi2 homodimer interface that mediates toxin interaction and immunity. Consistent with this finding, we observed that destabilization of the Tsi2 dimer does not impact Tse2 interaction. The molecular insights into Tsi2 structure and function garnered from this study shed light on the mechanisms of T6 effector secretion, and indicate that the Tse2-Tsi2 effector-immunity pair has features distinguishing it from previously characterized toxin-immunity and toxin-antitoxin systems.

PubMed: 22511866
DOI: 10.1371/journal.ppat.1002613

実験手法

X-RAY DIFFRACTION (1 Å)