Journal article
Coordinated rearrangements between cytoplasmic and periplasmic domains of the membrane protein complex ExbB-ExbD of escherichia coli
A Sverzhinsky, L Fabre, AL Cottreau, DMP Biot-Pelletier, S Khalil, M Bostina, I Rouiller, JW Coulton
Structure | CELL PRESS | Published : 2014
Abstract
Gram-negative bacteria rely on the ExbB-ExbD-TonB system for the import of essential nutrients. Despite decades of research, the stoichiometry, subunit organization, and mechanism of action of the membrane proteins of the Ton system remain unclear. We copurified ExbB with ExbD as an ∼240 kDa protein-detergent complex, measured by light scattering and by native gels. Quantitative Coomassie staining revealed a stoichiometry of ExbB 4-ExbD2. Negative stain electron microscopy and 2D analysis showed particles of ∼10 nm diameter in multiple structural states. Nanogold labeling identified the position of the ExbD periplasmic domain. Random conical tilt was used to reconstruct the particles in thre..
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Awarded by McGill University
Funding Acknowledgements
This work was supported by operating grants to J.W.C. from the Canadian Institutes of Health Research (CIHR reference number 200709MOP-178048-BMA-CFAA-11449) and I.R. (CIHR reference number 86693MOP). I.R. is a CIHR New Investigator. The Groupe d'etude des proteines membranaires (GEPROM), supported by the Fonds de la recherche en santedu Quebec (FRSQ), awarded a Projet Novateur to both principal investigators. A.S. was awarded fellowships from the CREATE program, Cellular Dynamics of Macromolecular Complexes, Natural Sciences and Research Engineering Council (NSERC) of Canada; GEPROM; and the F.C. Harrison and the Rozanis Funds, Department of Microbiology and Immunology, McGill University. L.F. and A.L.C. were awarded fellowships from GEPROM. D.B.-P. received a PGS-M scholarship from NSERC and an international training award from FRSQ. Canada Foundation for Innovation provided infrastructure for the Facility for Electron Microscope Research, McGill University (http://www.medicine.mcgill.ca/femr/home.html). Mass spectrometry services were provided by Marcos Di Falco, Genome Quebec Proteomics Platform. This work was facilitated by computing resources from CLUMEQ under Compute/Calcul Canada. We appreciate laboratory support from Nathalie Croteau and suggestions on the manuscript by B. Cousineau, J.M. Kollman, and J. Kashul. This paper is dedicated to Professor R.G.E. Murray, electron microscopist, who celebrates his 70th year of graduation (1943) from McGill University.