9P0A

Structure of Natrinema sp. J7-2 Tafi pilus

9P0A の概要

• エントリーDOI: 10.2210/pdb9p0a/pdb
• EMDBエントリー: 71067
• 分子名称: Pilin (1 entity in total)
• 機能のキーワード: extrcellular filament, bundling pili, protein fibril
• 由来する生物種: Natrinema sp. J7-2
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 65085.58

構造登録者

Sonani, R.R.,Egelman, E.H. (登録日: 2025-06-06, 公開日: 2025-07-23, 最終更新日: 2025-11-19)

主引用文献

Sonani, R.R.,Liu, Y.,Xiang, J.,Cvirkaite-Krupovic, V.,Du, S.,Chen, X.,Krupovic, M.,Egelman, E.H.
Tat-dependent bundling pilus of a halophilic archaeon assembles by a strand donation mechanism and facilitates biofilm formation.
Proc.Natl.Acad.Sci.USA, 122:e2514980122-e2514980122, 2025

PubMed Abstract: Diverse extracellular filaments present on the surface of archaea mediate multiple key processes, such as motility, adhesion, and biofilm formation. Although several archaeal filament types have been characterized in considerable detail, many remain understudied, particularly those utilizing noncanonical secretion systems. Here, we describe the Tafi bundling pilus that facilitates biofilm formation in the haloarchaeon sp. J7-2. Unlike previously characterized archaeal pili, Tafi is secreted via the twin-arginine translocation (Tat) pathway, which transports fully folded proteins across the cytoplasmic membrane. Structural analysis reveals that although Tafi pili assemble via a canonical strand-donation mechanism, the pilin subunit (TafE) adopts a distinct structural topology that sets it apart from the previously characterized Sec-dependent pilins that form bundling pili in archaea. Sequence analyses show that TafE homologs are also present in thermophilic archaea from different phyla, but Tat-signal sequences are exclusive to pilins of halophilic archaea. Nevertheless, we find that Tat signal peptides in haloarchaeal TafE-like pili were exchanged back to the Sec signal peptides on multiple independent occasions. These findings expand our understanding of the diversity and evolution of archaeal extracellular filaments and highlight the Tat pathway as a route for pilus assembly in halophilic archaea.

PubMed: 40737320
DOI: 10.1073/pnas.2514980122

実験手法

ELECTRON MICROSCOPY (4.2 Å)