The multidrug resistance efflux complex, EmrAB from Escherichia coli forms a dimer in vitro
- Division of Molecular Biosciences, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT (United Kingdom)
- Division of Cell and Molecular Biology, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS (United Kingdom)
Tripartite efflux systems are responsible for the export of toxins across both the inner and outer membranes of Gram negative bacteria. Previous work has indicated that EmrAB-TolC from Escherichia coli is such a tripartite system, comprised of EmrB an MFS transporter, EmrA, a membrane fusion protein and TolC, an outer membrane channel. The whole complex is predicted to form a continuous channel allowing direct export from the cytoplasm to the exterior of the cell. Little is known, however, about the interactions between the individual components of this system. Reconstitution of EmrA + EmrB resulted in co-elution of the two proteins from a gel filtration column indicating formation of the EmrAB complex. Electron microscopic single particle analysis of the reconstituted EmrAB complex revealed the presence of particles approximately 240 x 140 A, likely to correspond to two EmrAB dimers in a back-to-back arrangement, suggesting the dimeric EmrAB form is the physiological state contrasting with the trimeric arrangement of the AcrAB-TolC system.
- OSTI ID:
- 21255916
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 380, Issue 2; Other Information: DOI: 10.1016/j.bbrc.2009.01.081; PII: S0006-291X(09)00118-1; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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