Professor Bren's research interests lie in the fields of bioinorganic and biophysical chemistry. The Bren group is working toward understanding relationships between structure, folding, dynamics, and stability of heme proteins in the cytochrome c family. The heme chromophore serves as a valuable spectroscopic probe of protein folding and dynamics, and the Bren group takes advantage of this by employing a number of spectroscopic techniques, including paramagnetic NMR, resonance Raman, and fluorescence energy transfer. In addition, the Bren group uses a variety of biochemical techniques including site-directed mutagenesis and protein expression. Students in the Bren group have the opportunity to learn a wide range of approaches to a problem.

One major project involves the study of interrelationships between dynamics, stability, and electron transfer activity of heme-containing electron transfer proteins, cytochromes c. A goal of this project is to gain an understanding of how motions of the polypeptide backbone about the average structure impact heme electronic structure and redox potential, and how the protein sequence modulates those motions. To tackle this problem, NMR and resonance Raman experiments are being performed to characterize the motions and conformations of the cytochrome c polypeptide and heme group. The results obtained in this work will help us gain a more complete understanding of how nature controls electron transfer reactions.

The Bren group uses spectroscopy to investigate cytochrome c folding and dynamics.

In a second project being done in collaboration with UR Professors Todd Krauss and Harry Stern, the Bren group is exploring protein folding using cytochromes c as a model system. A primary focus is to characterize the heterogeneity of folding by employing single-molecule spectroscopic methods. In addition, NMR experiments on unfolded and partially unfolded cytochromes are informing us of details of the conformations sampled by unfolded polypeptides; we hypothesize that these conformations play a key role in directing folding. Ultimately, we aim to fully characterize the folding energy landscape of proteins in this ubiquitous family.