Richard G. Brennan, Ph.D. 1984, University of Wisconsin - Madison UT M. D. Anderson Cancer Center Biochemistry and Molecular Biology Contact Information

Research Interests: Multidrug resistance, protein-nucleic interaction, regulation of gene expression; oxidative stress responses; protein-ligand interaction, toxin-antitoxin structure and function; macromolecular crystallography

The research in my laboratory focuses on understanding the structural mechanisms that underlie multiple biological processes. One major aspect of the laboratory’s research is to delineate the mechanisms by which single proteins are able to recognize and bind multiple, chemically and structurally dissimilar drugs, i.e., how proteins contribute to multidrug resistance and multidrug tolerance. Just how a single protein can bind multiple, structurally and chemically dissimilar compounds is a fascinating problem. As part of this interest, we employ biochemical, molecular biological and crystallographic tools to study transcription factors that are multidrug binding proteins. In addition to their multidrug binding properties, we are very interested in understanding their mechanisms of gene regulation, i.e., their DNA binding properties and mechanisms of induction. In a related light, we also study how global regulators such as CcpA, TnrA and Hfq respond to a variety of metabolic cues in order to carry out their gene regulatory functions. Another major research interest is the structural response by transcription factors to a variety of oxidative stresses such that the cell is able to survive the presence of reactive oxygen species, such as organic hydroperoxides, and to overcome disulphide stress. We are developing a strong interest in bacterial “toxin-antitoxin” systems, which in reality are sensors of different cellular stresses that result in the release of the “toxin”, which to date have been shown to be proteins with a wide variety of catalytic properties, to effect the appropriate response. Finally, we are taking on a slew of new projects that deal with the underlying mechanisms of oncogenesis. These studies involve structural studies on protein-protein complexes, the dysregulation of which lead to improper signal transduction and uncontrolled cellular proliferation.

A tutorial in my laboratory would combine biochemical and crystallographic methods in order to study the structure-function relationships of one of these proteins. Depending upon which system is chosen, a tutorial student would learn how to create one or more site-directed mutants, purify the resulting protein(s), characterize the biochemical function(s) of selected mutants, e.g., their DNA or ligand binding properties, set up crystallization experiments, and if time permitting collect x-ray intensity data and begin the process of structure determination and refinement.
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Zheleznova Heldwein EE, Brennan RG (2001) Crystal structure of the transcription activator BmrR bound to DNA and a drug. Nature 409:378-382.

Schumacher MA, Miller MC, Grkovic S, Brown MH, Skurray RA, Brennan RG (2001) Structural Mechanisms of QacR Induction and Multidrug Recognition. Science 294:2158-2163.

Schumacher MA, Miller MC, Grkovic S, Brown MH, Skurray RA, Brennan RG (2002) Structural basis for cooperative DNA binding by two dimers of the multidrug binding protein QacR. EMBO J. 21:1210-1218.

Schumacher MA, Miller RF, Møller T, Valentin-Hansen P, Brennan RG (2002) Structures of the pleiotropic translational regulator Hfq and an Hfq-RNA complex; a bacterial Sm-like protein. EMBO J. 21:3546-3556.

Schumacher MA, Miller MC, Brennan RG (2004) Structural mechanism of the simultaneous binding of two drugs to a multidrug-binding protein. EMBO J, 23:2923-2930.

Schumacher MA, Allen GS, Diel M, Seidel G, Hillen W, Brennan RG (2004) Structural basis for allosteric control of the transcription regulator CcpA by the phosphoprotein HPr-Ser46-P. Cell, 118:731-741.

Newberry KJ, Brennan RG (2004) The Structural Mechanism of Transcription Activation by MerR Family Member MtaN. J Biol Chem. 279:20356-20362.

Hong M, Fuangthong M, Helmann JD, Brennan RG (2005) Structure of an OhrR-ohrA operator complex reveals the DNA binding mechanism of the MarR family. Molecular Cell. 20:131-141.

Newberry KJ, Nakano S, Zuber P, Brennan RG (2005) Crystal structure of the Bacillus subtilis anti alpha, global transcriptional regulator, Spx, in complex with the a C-terminal domain of RNA polymerase. Proc Natl Acad Sci, USA (Track II) 102:15839-15844. Published online before print October 25 2005, 10.1073/pnas.0506592102

Mattison K, Wilbur JS, So M, Brennan RG (2006) Structure of FitAB from Neisseria gonorrhoeae bound to DNA reveals a tetramer of toxin-antitoxin heterodimers containing PIN domains and DNA binding ribbon-helix-helix motifs. In press, J Biol Chem. First published as Papers in Press, September 18, 2006 as Manuscript M605198200.

Schumacher MA, Seidel G, Hillen W, Brennan RG (2006) Phosphoprotein Crh-Ser-46-P displays altered binding to CcpA to effect carbon catabolite regulation. J Biol Chem 281:6793-6780. First published as Papers in Press, November 29, 2005 as Manuscript M509977200.

Brennan RG, Link TM (2007) Hfq Structure, Function and Ligand Binding. Curr Opin Microbiol.10:125-133.

Brooks BE, Piro KM, Brennan RG (2007) The Multidrug-Binding Transcription Factor, QacR, Binds the Bivalent Aromatic Diamidines DB75 and DB359 in Multiple Positions. J Amer Chem Soc.129:8389-8395.

Newberry KJ, Fuangthong M, Panmanee W, Mongkolsuk S, Brennan RG (2007) Structural Mechanism of Organic Hydroperoxide Induction of the Transcription Regulator OhrR. Mol Cell. 28:652-664.

Shelburne III SA, Keith D, Horstmann N, Sumby P, Davenport MT, Graviss EA, Brennan RG, Musser JM (2008) A direct link between carbohydrate utilization and virulence in the major human pathogen group A Streptococcus. In press, Proc Natl Acad Sci, USA.

Amen M, Espinoza HM, Cox C, Liang X, Wang J, Link TM, Brennan RG, Martin JF, Amendt BA (2008) Chromatin-Associated HMG-17 is a Major Regulator of Homeodomain Transcription Factor Activity Modulated by Wnt/ b -catenin Signalling. Nucl Acids Res. 36:462-476.

Program Affiliation:
Program in Genes and Development