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Updated: Oct 9, 2026

Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution
Published on: August 16, 2016
Chunnel vision. Export and efflux through bacterial channel-tunnels
C Andersen1, C Hughes, V Koronakis
1University of Cambridge Department of Pathology, UK.
Abstract:
The Escherichia coli TolC protein is central to toxin export and drug efflux across the inner and outer cell membranes and the intervening periplasmic space. The crystal structure has revealed that TolC assembles into a remarkable alpha-helical trans-periplasmic cylinder (tunnel) embedded in the outer membrane by a contiguous beta-barrel (channel), so providing a large duct open to the outside environment. The channel-tunnel structure is conserved in TolC homologues throughout Gram-negative bacteria, and it is envisaged that they are recruited and opened, through a common mechanism, by substrate-specific inner-membrane complexes.
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