6UIE

Structure of the cytoplasmic domain of the T3SS sorting platform protein PscK from P. aeruginosa

6UIE の概要

• エントリーDOI: 10.2210/pdb6uie/pdb
• 分子名称: Type III export protein PscK, CHLORIDE ION (2 entities in total)
• 機能のキーワード: psck, type iii secretion apparatus protein, transport 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: 48464.74

構造登録者

Muthuramalingam, M.,Lovell, S.,Battaile, K.P.,Picking, W.D. (登録日: 2019-09-30, 公開日: 2020-10-07, 最終更新日: 2024-11-06)

主引用文献

Muthuramalingam, M.,Whittier, S.K.,Lovell, S.,Battaile, K.P.,Tachiyama, S.,Johnson, D.K.,Picking, W.L.,Picking, W.D.
The Structures of SctK and SctD from Pseudomonas aeruginosa Reveal the Interface of the Type III Secretion System Basal Body and Sorting Platform.
J.Mol.Biol., 432:166693-166693, 2020

PubMed Abstract: Many Gram-negative bacterial pathogens use type III secretion systems (T3SS) to inject proteins into eukaryotic cells to subvert normal cellular functions. The T3SS apparatus (injectisome) shares a common architecture in all systems studied thus far, comprising three major components - the cytoplasmic sorting platform, envelope-spanning basal body and external needle with tip complex. The sorting platform consists of an ATPase (SctN) connected to "pods" (SctQ) having six-fold symmetry via radial spokes (SctL). These pods interface with the 24-fold symmetric SctD inner membrane ring (IR) via an adaptor protein (SctK). Here we report the first high-resolution structure of a SctK protein family member, PscK from Pseudomonas aeruginosa, as well as the structure of its interacting partner, the cytoplasmic domain of PscD (SctD). The cytoplasmic domain of PscD forms a forkhead-associated (FHA) fold, like that of its homologues from other T3SS. PscK, on the other hand, forms a helix-rich structure that does not resemble any known protein fold. Based on these structural findings, we present the first model for an interaction between proteins from the sorting platform and the IR. We also test the importance of the PscD residues predicted to mediate this electrostatic interaction using a two-hybrid analysis. The functional need for these residues in vivo was then confirmed by monitoring secretion of the effector ExoU. These structures will contribute to the development of atomic-resolution models of the entire sorting platform and to our understanding of the mechanistic interface between the sorting platform and the basal body of the injectisome.

PubMed: 33122003
DOI: 10.1016/j.jmb.2020.10.027

実験手法

X-RAY DIFFRACTION (2.55 Å)