Many bacteria swim using flagella, and can direct their movement toward favorable conditions by regulating the direction of flagellar rotation in response to various sensory cues. We are trying to understand the structure and mechanism of the flagellar rotary motor. The motor is fueled by a flow of ions--either protons or sodium ions--across the membrane. We are using biochemical, genetic, and structural approaches to understand how ion flow is harnessed to produce useful work, and how the motor controls the switch between clockwise and counter-clockwise rotation. The flagellum is built with the aid of a dedicated protein-export apparatus that is closely related to an export machine used by pathogens to inject harmful effectors into host cells. This apparatus operates at enormous rates yet is highly specific for the appropriate substrates; like the motor, it is energized by the proton gradient. We are also seeking to understand the structure and mechanism of the flagellar export machinery and, by extension, the virulence apparatus of pathogens.
- Boschert, R., Adler, F., and Blair, D.F. Loose coupling in the bacterial flagellar motor. Proc. Natl. Acad. Sci. USA doi: 10.1073/pnas.1419955112 (2015).
- Kim, E.A, and Blair, D.F. Function of the histone-like protein H-NS in motility of Escherichia coli: Multiple regulatory roles rather than direct action at the flagellar motor. J. Bacteriol. 197(19), 3110-3120. doi: 10.1128/JB.00309-15 (2015).
- Lynch, M.J., Levenson, R., Kim, E.A, Sircar, R., Blair, D.F., Dahlquist, F.W., and Crane, B.R. Co-folding of a FliF-FliG split domain forms the basis of the MS:C-ring interface within the bacterial flagellar motor. Structure 25, 317-328. doi: 10j.1016/j.str.2016.12.006 (2016).
- Erhardt, M., Wheatley, P., Kim, E.A, Hirano, T., Zhang, Y., Sarkar, M.K., Hughes, K.T., and Blair D.F. Mechanism of type-III protein secretion: Regulation of FlhA conformation by a functionally critical charged-residue cluster. Mol. Microbiol., in press.
- Kim, E.A, Panushka, J., Meyer, T., Carlisle, R., Baker, S., Ide, N., Lynch, M., Crane, B.R., and Blair D.F. Architecture of the flagellar switch complex of Escherichia coli: conformational plasticity of FliG and implications for adaptive remodeling. J. Mol. Biol., in press.
- Biol 3510: Biological Chemistry
- Biol 3525: Nucleic Acids Biochemistry
- BLCHM 6450: Biophysical Chemistry