Scholarlink

<p>The Type IX Secretion System exports proteins across the outer membrane (OM) of bacteria in the Bacteroidota phylum, however, the mechanistic details remain unknown. In <i>Porphyromonas gingivalis</i> the core components of the multi-protein complex are the Sov translocon, Attachment Complexes (PorQ, U, V, Z), PorLM molecular motors and PorKN rings. Here, we present a ~ 3.5 Å cryo-EM structure of the periplasmic rings comprising 32–33 subunits each of PorK and PorN. Additionally, we show the presence of a critical disulfide bond between PorK and the OM protein PorG that is essential for protein secretion and demonstrate that the Attachment Complexes bind to, and are localized above, the PorKN rings. Overall, each ring resembles a cogwheel with PorN forming cog-like projections that we propose engage with the PorLM motor to drive the rotation of the PorKN cogwheel together with PorG and associated Attachment Complexes, thus providing the energy to complete protein secretion and the coordinated cell surface attachment of the secreted cargo.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Insights into type IX secretion from PorKN cogwheel structure bound to PorG and attachment complexes

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年8月19日

查看全文
  • Dhana G. Gorasia,
  • Eric Hanssen,
  • Manasi Mudaliyar,
  • Craig J. Morton,
  • Sepideh Valimehr,
  • Christine Seers,
  • Lianyi Zhang,
  • Matthew T. Doyle,
  • Debnath Ghosal,
  • Paul D. Veith,
  • Eric C. Reynolds

摘要

The Type IX Secretion System exports proteins across the outer membrane (OM) of bacteria in the Bacteroidota phylum, however, the mechanistic details remain unknown. In Porphyromonas gingivalis the core components of the multi-protein complex are the Sov translocon, Attachment Complexes (PorQ, U, V, Z), PorLM molecular motors and PorKN rings. Here, we present a ~ 3.5 Å cryo-EM structure of the periplasmic rings comprising 32–33 subunits each of PorK and PorN. Additionally, we show the presence of a critical disulfide bond between PorK and the OM protein PorG that is essential for protein secretion and demonstrate that the Attachment Complexes bind to, and are localized above, the PorKN rings. Overall, each ring resembles a cogwheel with PorN forming cog-like projections that we propose engage with the PorLM motor to drive the rotation of the PorKN cogwheel together with PorG and associated Attachment Complexes, thus providing the energy to complete protein secretion and the coordinated cell surface attachment of the secreted cargo.