Professor Bren's research interests lie in the fields of bioinorganic and biophysical chemistry. The Bren group has developed new methods for engineering and characterizing metalloproteins in the cytochrome c family, contributing to our understanding of how protein structure dictates protein dynamics and function. In ongoing work, we are employing a range of spectroscopic techniques to understand how the three-dimensional structure of metalloproteins influences their electronic structure and reactivity.
In another major effort, the Bren group is developing metalloprotein- and metallopeptide-based catalysts with particular relevance to energy conversion. Metallobiomolecular catalysts offer a number of advantages including being water soluble and environmentally friendly. Furthermore, the use of protein engineering facilitates the preparation of multifunctional and modular structures and the manipulation of second-sphere interactions within the catalytic site.
A current emphasis in the lab is the development of artificial hydrogenases, or enzymes that catalyze the reduction of protons derived from water to hydrogen (H2). Hydrogen produced from water is a green, carbon-free fuel, and hydrogen evolution driven by sunlight stores solar energy in the form of chemical bonds. The Bren group's artificial hydrogenases couple to synthetic, biomolecular, or nanotechnological photosensitizers to yield environmentally friendly assemblies to produce hydrogen as a solar fuel. The ultimate goal is to produce elegant and efficient systems that perform artificial photosynthesis.
"NMR Analysis of Spin States and Spin Densities, in Spin States in Biochemistry and Inorganic Chemistry: Influence on Structure and Reactivity," Edited by M. Swart and M. Costas Wiley, John Wiley & Sons, Ltd, Chichester, United Kingdom 2016.
Bren, K.L., Eisenberg, R., Gray, H.B. "Discovery of the Magnetic Behavior of Hemoglobin: A Beginning of Bioinorganic Chemistry," Proc. Natl. Acad. Sci. U.S.A. 2015, in press.
Sun, Y., Benabbas, A., Zeng, W., Kleingardner, J.G., Bren, K.L., Champion, P.M. "Investigations of Heme Distortion, Low-Frequency Vibrational Excitations, and Electron Transfer in Cytochrome c," Proc. Natl. Acad. Sci. USA 2014, 111, 6570-6575. http://dx.doi.org/10.1073/pnas.1322274111
Kleingardner, J.G., Kandemeir, B., Bren, K.L. "Hydrogen Evolution from Neutral Water Under Aerobic Conditions Catalyzed by Cobalt-microperoxidase-11," J. Am. Chem. Soc. 2014, 136, 4-7. http://dx.doi.org/10.1021/ja406818h
Kleingardner, J.G., Bowman, S.E.J., Bren, K.L. "The Influence of Heme Ruffling on Spin Densities in Ferricytochromes c Probed by Heme Core 13C NMR," Inorg. Chem 2013, 52, 12933-12946. http://dx.doi.org/10.1021/ic401250d
Kaur, R, Bren, K.L. "Redox State Dependence of Axial Ligand Dynamics in Nitrosomonas europaea Cytochrome c552," J. Phys. Chem. B 2013, 117, 15720-15728. http://dx.doi.org/10.1021/jp4064577
Lee, A.J, Asher, W.B., Stern, H.A., Bren, K.L., Krauss, T.D. "Single-molecule Analysis of Cytochrome c Folding by Monitoring the Lifetime of an Attached Fluorescent Probe," J. Phys. Chem. Lett 2013, 4, 2727-2733. http://dx.doi.org/10.1021/jz401259y
Can, M., Krucinska, J., Zoppallero, G., Andersen, N.H., Wedekind, J.E., Hersleth, H.P., Andersson, K.K., Bren, K.L. "Structural Characterization of Nitrosomonas europaea Cytochrome c552 Variants with Marked Differences in Electronic Structure," ChemBioChem 2013, 13, 1828-1838. http://dx.doi.org/10.1002/cbic.201300118 (Spotlight in Angewandte Chemie
Josephs, T.M., Liptak, M.D., Hughes, G., Lo, A., Smith, R.M., Wilbanks, S.M., Bren, K. L., Ledgerwood, E.C. "Conformational Change and Human Cytochrome c Function: Mutation of Residue 41 Modulates Caspase Activation and Destabilizes Met-80 Coordination," J. Biol. Inorg. Chem. 2013, 18, 289-297.