Ray Larsen

Research Interests:

Our laboratory is focused on the mechanisms of energy-coupling to transport events in the envelope of gram negative bacteria.  Current studies include:

• Structural requisites for energy transfer in the TonB system
• Determinants of host range specificity in phage that exploit active transport systems
• Mechanisms of bacterial toxin transmembrane transport
• And, for something completely different, evolution of beta-lactamase proteins in the soil microbiome.

Selected Publications:

Larsen, R.A. 2017.  Assessing energy-dependent protein conformational changes in the TonB system.  In:  Bacterial Secretion Systems.  E. Cascales , L. Journet (ed).  Springer Verlag.  Berlin.

Teleha, M.A., Miller, A.C., and Larsen, R.A.  2013.  Overexpression of the Escherichia coli TolQ protein leads to a null-FtsN-like division phenotype.  Microbiology Open 2:618-632.

Gresock, M. G., M. I. Savenkova, R. A. Larsen, A. A. Ollis, and K. Postle. 2011. Death of the TonB shuttle hypothesis. Front. Microbiol. 2: 1-8.

Brinkman, K.K., and R.A. Larsen. 2008. Interactions of the energy transducer TonB with noncognate energy-harvesting complexes. J. Bacteriol. 190: 421-427.

Weitzel, A.C., and R.A. Larsen. 2008. Differential complementation of ∆toA Escherichia coli by a Yersinia enterocolitica TolA homologue. FEMS Micro Lett 282: 81-88.

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.