My general interests lie in understanding the forces that control protein-protein interactions. My work has focused on developing and applying novel experimental methods to characterize these interactions in areas such as protein crystallization, protein-surfactant interactions, membrane protein folding and engineering specificity of transmembrane helix-helix interactions.

My graduate work at the University of Delaware (advisors: Abraham Lenhoff, Eric Kaler) was focused on characterizing protein and surfactant interactions as they relate to protein crystallization. I used a variety of experimental techniques, including dynamic light scattering, self-interaction chromatography and isothermal titration calorimetry, to study the phase behavior of protein-surfactant mixtures in the presence of a wide range of additives and precipitants. By relating surfactant phase behavior to interactions between protein-detergent complexes (PDCs) in terms of the osmotic second virial coefficient (B₂₂), I established patterns of crystallization for both the integral membrane protein bacteriorhodopsin (BR) and soluble protein calcium- and integrin-binding protein (CIB). My results led to a greater understanding of the various influences additives and precipitants have on the interplay between PDC interactions and surfactant phase behavior, and how these interactions can be manipulated to favor PDC crystallization.

As a post-doctoral fellow at the University of Pennsylvania School of Medicine (advisors: Joel Bennett, William DeGrado), I have been investigating factors that contribute to transmembrane (TM) helix-helix interactions and stability. Much of this work has focused on integrins, a family of heterodimeric, cell-surface receptors involved in cell adhesion and signal transduction. I have developed genetic methods to examine the specificity of the homo- and heterooligomeric interactions involving integrin TM domains in membranes, identified key residues and interactions motifs through scanning mutagenesis and characterized effects of these mutations on integrin function in vivo. I have also used these methods to examine the specificity of designed peptides that target TM domains such as integrins.

Representative Publications:

1. Berger BW, Bennett JS, WF DeGrado*. Homo- and Heterooligomerization of Integrin Transmembrane Domains. In preparation (2008)

2. Yin H, Slusky JA, Berger BW, Walters RS, Vilaire G, Litvinov RI, Lear JD, Caputo GA, Bennett JS, WF DeGrado*. Computational Design of Peptides That Target Transmembrane Helices. Science 315 (2007) 1817-1822

3. BW Berger*, Gendron CM, Lenhoff AM, EW Kaler*. Effects of additives on surfactant phase behavior relevant to bacteriorhodopsin crystallization. Protein Science 15 (2006) 2682-2696 (feature article, see also accompanying commentary: MC Wiener. When worlds colloid. Protein Science 15 (2006) 2679-2681)

4. Berger BW, Gendron CM, Robinson CR, Kaler EW, AM Lenhoff*. The role of protein and surfactant interactions in membrane-protein crystallization. Acta Crystallographica D61 (2005) 724-730

5. Berger BW, Blamey CJ, Bahnson BJ, AM Lenhoff*. Role of additives and precipitants in crystallization of calcium- and integrin-binding protein. Crystal Growth and Design 5 (2005) 1499-1507