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3258 TAMU Office: Lab: Fax: 979-845-2891 |
Biography |
| Mike Manson (b. 1947) received his B.A. degree from Johns Hopkins and his Ph.D. under Charles Yanofsky at Stanford. After postdoctoral study with Howard Berg at the University of Colorado and Caltech, he spent five years with Winfried Boos at the University of Konstanz, Germany. At Texas A&M since 1987, he is now a Professor of Biology. | |
| Bacterial Behavior | |
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Bacteria have a limited behavioral repertoire. The well-known Gram-negative enteric species Escherichia coli swims after nutrients that the cells smell. The simplicity of bacterial motility and chemotaxis, and the amenability of E. coli to genetic, biochemical and physiological manipulation, has facilitated rapid advances in understanding the molecular mechanisms of biological energy conversion and signal transduction. Our laboratory studies the inputs and outputs of chemotaxis. Ligands interact with the periplasmic receptor domain of a chemotactic signal transducer that spans the cytoplasmic membrane. This interaction is converted into an intracellular signal that is communicated to the flagella. Our most detailed analysis has been made with the aspartate/maltose receptor, which binds aspartate directly. In contrast, maltose first binds to a soluble periplasmic protein, which then interacts with the receptor domain of the transducer. Thus, an acidic amino acid and a moderately large protein each evokes an attractant signal from the same receptor. We know to a fairly high degree of molecular detail how these ligands bind. We are now extending our investigations to probe the conformational changes in the transducer that accompany transmembrane signaling. We are also working to determine the mechanism of repellent sensing. We also want to know how transmembrane H+ current is converted into flagellar rotation. We find that certain missense mutations affecting mobility proteins are suppressed by mutations in genes encoding other motility or flagellar proteins. This analysis is being extended to reveal protein interactions in the flagellum that drive this, the world's tiniest, rotary motor. Co-expression of specific combinations of mutant motility proteins in large amounts is lethal. We have found that mutation in a region we call the “plug” of MotB lead to a constitutively open proton channel. The plug consists of an amphipathic helix that we think interacts with the cell membrane to block the channel. We are trying to work out the molecular mechanisms that trigger the opening and closing of the channel. We are also studying the role of a protein "hinge" in switching the direction of flagellar rotation and determining how the stator element of the motor is anchored to the cell wall. |
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| Selected Publications | |
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Ward, S.M. Bormans, A.F., and Manson, M.D. (2006) Mutationally altered signal output in the Nart (NarX-Tar) hybrid chemoreceptor. J. Bacteriol. 188: 3944-3951. Draheim, R.R., Bormans, A.F., Lai, R.-Z., and Manson, M.D. (2006) Tuning a bacterial chemoreceptor with protein-membrane interactions. Biochemistry 45: 14655-14664. Hosking, E.R., Vogt, C., Bakker, E.P., and Manson, M.D. (2006) The Escherichia coli MotAB proton channel unplugged. J. Mol. Biol. 364: 921-937. Draheim, R.R., Bormans, A.F., Lai, R.-Z., and Manson, M.D. (2005) Tryptophan residues flanking the second transmembrane helix (TM2) set the signaling state of the Tar chemoreceptor. Biochemistry 44: 1268-1277. Lai, R.-Z., Manson, J.M., Bormans, A.F., Draheim, R.R., Nguyen, N.T., and Manson, M.D. (2005) Cooperative signaling among bacterial chemoreceptors. Biochemistry 44: 14298-14307. Van Way, S.M., Millas, S.G., Lee, A.H., and Manson, M.D. (2004) Rusty, jammed, and well-oiled hinges: Mutations affecting the interdomain region of FliG, a rotor element of the Escherichia coli flagellar motor. J. Bacteriol. 186: 3173-3181. Mao, H., Cremer, P.S., and Manson, M.D. (2003) A sensitive, versatile microfluidic assay for bacterial chemotaxis. Proc. Natl. Acad. Sci. USA 100: 5449-5454. Cantwell, B.J., R. Draheim, R.B. Weart, C. Nguyen, and M.D. Manson. 2002. CheZ localization to the chemoreceptor patch requires CheAshort. J. Bacteriol. (in press). Ward, S.M., A. Delgado, R.P. Gunsalus, and M.D. Manson. 2002. A NarX-Tar chimera mediates repellent chemotaxis to nitrate and nitrite. Mol. Microbiol. (in press). Gründling, A., M.D. Manson, and R. Young. 2001. Holins kill without warning. Proc. Natl. Acad. Sci. USA 98: 9348-9352. Manson, M.D., and B.J. Cantwell. 2000. Model is as model does. Nature Cell Biol. 2: E199-201. Van Way, S.M., E.R. Hosking, T.F. Braun, and M.D. Manson. 2000. Mot protein assembly into the bacterial flagellum: A model based on mutational analysis of the motB gene. J. Mol. Biol. 297: 7-24. Manson, M.D. 2000. Allele-specific suppression as a tool to study protein-protein interactions in bacteria. Methods 20: 18-34. Zhang, Y., P.J. Gardina, A.S. Kuebler, H.S. Kang, J.A. Christopher, and M.D. Manson. 1999. Model of maltose-binding protein/chemoreceptor complex supports intrasubunit signaling mechanism. Proc. Natl. Acad. Sci. USA 96: 939-944. Gardina, P.J., A.F. Bormans, and M.D. Manson. 1998. A mechanism for simultaneous sensing of aspartate and maltose by the Tar chemoreceptor of Escherichia coli. Mol. Microbiol. 29: 1147-1154. |
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