Ph. D., Institution

   

Office:    431 Life Sciences Building

Phone:   1-419-372-9559

Email:     larsera@bgnet.bgsu.edu

   

 

Research:

Transport and membrane energetics in bacteria

   

 

 

   

 

   

Research Interests:

My laboratory uses genetic and biochemical approaches to examine the mechanism by which the cytoplasmic membrane ion electrochemical potential is harnessed to energize the biogenesis and maintenance of the essentially non-energized outer membrane of Gram negative bacteria. Because the outer membrane is the principle interface between the organism and the environment, these studies impact a broad set of biological issues; ranging from ecology to pathogenesis (although the molecular biology and energetics are alone more than sufficient to keep us all very busy).

Selected Publications:

Keller, K. L., K. K. Brinkman, and R. A. Larsen. 2007. TonB/TolA amino-terminal domain modeling. Methods in Enzymology 423:134-148.

Larsen, R.A., G.E. Deckert, K.A. Kastead, S. Devanathan, K. L. Keller, and K. Postle. 2007. His₂₀ provides the sole functionally significant side chain in the essential TonB transmembrane domain. J. Bacteriol. 189:2825-2833.

Postle, K., and Larsen, R. A. 2007. TonB-dependent energy transduction between outer and cytoplasmic membranes. BioMetals. 20:453-465.

Postle, K., and R.A. Larsen. 2005. The TonB, Ex6B, and ExbD proteins. In: Iron Tansport in Bacteria. Crosa, J.H., Mey, A.R., Payne, S.M. (eds). ASM Press, Washington. pp. 96-112.

Larsen, R.A., Chen, G.J., Postle, K. 2003. Performance of standard phenotypic assays for TonB activity, as evaluated by varying the relative levels of functional, wild-type TonB. J. Bacteriol. 185:4699-4706.

Larsen, R.A., Letain, T.E., Postle, K. 2003. In vivo evidence of TonB shuttling between the cytoplasmic and outer membranes of Escherichia coli. Mol. Microbiol., 49:211-218.

Higgs, P.I., Larsen, R.A., Postle, K. 2002. Per cell quantitation of the known components of the Escherichia coli TonB energy transduction system: TonB, ExbB, ExbD, and an outer membrane protein, FepA. Mol. Microbiol. 44:271-281.

Larsen, R.A., Postle, K. 2001. Conserved residues S16 and H20, and their relative positioning, are essential for TonB activity, cross-linking of TonB with ExbB, and the ability of TonB to respond to proton motive force. J. Biol. Chem. 276:8111-8117.

Larsen, R.A., Thomas, M.G., Postle, K. 1999. Protonmotive force, ExbB, and ligand-bound FepA drive conformational changes in TonB. Mol. Microbiol. 31:1809-1824.

Larsen, R.A., Foster-Hartnett, D., McIntosh, M. A., Postle, K. 1997. Regions of Escherichia coli TonB and FepA proteins essential for in vivo physical interactions. J. Bacteriol. 179:3213-3221.

Larsen, R.A., Myers, P.S., Skare, J.S., Darveau, R.P., Seachord, C.L., Postle, K. 1996. Identification of TonB homologues in Gram negative enterics by monoclonal antibodies specific for conserved TonB epitopes. J. Bacteriol. 178:1363-1373.

Ahmer, B.M.M, Thomas, M.G., Larsen, R.A., Postle, K. 1996. Characterization of the exbBD operon of Escherichia coli and the role of ExbB and ExbD in TonB function and stability. J. Bacteriol. 177:4742-4747.

Larsen, R.A., Thomas, M.G., Wood, G.E., Postle, K. 1994. Partial suppression of an Escherichia coli TonB transmembrane domain mutation (V17) by a missense mutation in ExbB. Mol. Microbiol. 13:627-640.

Larsen, R.A., Wood, G.E., Postle, K. 1993. The conserved proline-rich motif is not essential for energy transduction by Escherichia coli TonB protein. Mol. Microbiol. 10:943-953.

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