9AVI

TolQ inner membrane protein from Acinetobacter baumannii

Summary for 9AVI

• Entry DOI: 10.2210/pdb9avi/pdb
• EMDB information: 43902
• Descriptor: Tol-Pal system protein TolQ (1 entity in total)
• Functional Keywords: inner membrane protein complex, structural genomics, center for structural biology of infectious diseases, csbid, membrane protein
• Biological source: Acinetobacter baumannii
• Total number of polymer chains: 5
• Total formula weight: 126950.96

Authors

Quade, B.,Otwinowski, Z.,Borek, D.,Center for Structural Biology of Infectious Diseases (CSBID) (deposition date: 2024-03-03, release date: 2025-01-22, Last modification date: 2025-04-16)

Primary citation

Karimullina, E.,Guo, Y.,Khan, H.M.,Emde, T.,Quade, B.,Di Leo, R.,Otwinowski, Z.,Tieleman, D.P.,Borek, D.,Savchenko, A.
Structural architecture of TolQ-TolR inner membrane protein complex from opportunistic pathogen Acinetobacter baumannii.
Sci Adv, 11:eadq9845-eadq9845, 2025

PubMed Abstract: Gram-negative bacteria harness the proton motive force (PMF) within their inner membrane (IM) to uphold cell envelope integrity, an indispensable aspect for both division and survival. The IM TolQ-TolR complex is the essential part of the Tol-Pal system, serving as a conduit for PMF energy transfer to the outer membrane. Here we present cryo-electron microscopy reconstructions of TolQ in apo and TolR-bound forms at atomic resolution. The apo TolQ configuration manifests as a symmetric pentameric pore, featuring a transmembrane funnel leading toward a cytoplasmic chamber. In contrast, the TolQ-TolR complex assumes a proton nonpermeable stance, characterized by the TolQ pentamer's flexure to accommodate the TolR dimer, where two protomers undergo a translation-based relationship. Our structure-guided analysis and simulations support the rotor-stator mechanism of action, wherein the rotation of the TolQ pentamer harmonizes with the TolR protomers' interplay. These findings broaden our mechanistic comprehension of molecular stator units empowering critical functions within the Gram-negative bacterial cell envelope.

PubMed: 40184442
DOI: 10.1126/sciadv.adq9845

Experimental method

ELECTRON MICROSCOPY (3.02 Å)