7NB6

Structure of the autoinducer-2 exporter TqsA from E. coli

Summary for 7NB6

• Entry DOI: 10.2210/pdb7nb6/pdb
• EMDB information: 12256
• Descriptor: AI-2 transport protein TqsA (1 entity in total)
• Functional Keywords: cryo-em, membrane protein, autoinducer-2 exporter, quorum sensing, pentamer, protein oligomerization, structural protein
• Biological source: Escherichia coli (strain K12)
• Total number of polymer chains: 5
• Total formula weight: 187817.71

Authors

Khera, R.,Xie, H.,Michel, H. (deposition date: 2021-01-25, release date: 2022-05-11, Last modification date: 2024-07-10)

Primary citation

Khera, R.,Mehdipour, A.R.,Bolla, J.R.,Kahnt, J.,Welsch, S.,Ermler, U.,Muenke, C.,Robinson, C.V.,Hummer, G.,Xie, H.,Michel, H.
Cryo-EM structures of pentameric autoinducer-2 exporter from Escherichia coli reveal its transport mechanism.
Embo J., 41:e109990-e109990, 2022

PubMed Abstract: Bacteria utilize small extracellular molecules to communicate in order to collectively coordinate their behaviors in response to the population density. Autoinducer-2 (AI-2), a universal molecule for both intra- and inter-species communication, is involved in the regulation of biofilm formation, virulence, motility, chemotaxis, and antibiotic resistance. While many studies have been devoted to understanding the biosynthesis and sensing of AI-2, very little information is available on its export. The protein TqsA from Escherichia coli, which belongs to the AI-2 exporter superfamily, has been shown to export AI-2. Here, we report the cryogenic electron microscopic structures of two AI-2 exporters (TqsA and YdiK) from E. coli at 3.35 Å and 2.80 Å resolutions, respectively. Our structures suggest that the AI-2 exporter exists as a homo-pentameric complex. In silico molecular docking and native mass spectrometry experiments were employed to demonstrate the interaction between AI-2 and TqsA, and the results highlight the functional importance of two helical hairpins in substrate binding. We propose that each monomer works as an independent functional unit utilizing an elevator-type transport mechanism.

PubMed: 35698912
DOI: 10.15252/embj.2021109990

Experimental method

ELECTRON MICROSCOPY (3.3 Å)