Chunnel vision. Export and efflux through bacterial channel-tunnels.
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.
Andersen
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C
University of Cambridge Department of Pathology, UK.
Hughes
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Koronakis
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V
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D001692:Biological Transport; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007473:Ion Channels / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008958:Models, Molecular; D010802:Phylogeny; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D007473:Ion Channels; D026901:Membrane Transport Proteins; C073126:tolC protein, E coli