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Engineered Metallobiomolecules for Energy Conversion

Developing sustainable energy sources is a major challenge facing humanity. Among alternative fuels, hydrogen (H2) is attractive because it is energy-dense and carbon-free. To be truly carbon free, H2 needs to be produced from carbon-free sources, with water being the most attractive. The Bren group, in collaboration with the Eisenberg and Krauss groups at U of R, is engineering systems for light-driven hydrogen evolution from water. In our part of this collaboration, the Bren group has developed methods for engineering cytochromes to act in photoinduced charge transfer and in catalysis of proton reduction. 

Manganese Porphyrins as MRI Contrast Agents

Manganese porphyrins are effective MRI contrast agents with lower toxicity than gadolinium. Furthermore, they display enhanced relaxivity at higher magnetic field, behavior that is the opposite of gadolinium agents. In collaboration with Xiao-an Zhang of the University of Toronto, we are employing NMR to investigate the electronic structure of manganese porphyrin contrast agents to understand factors that impact their relaxivity.

Heme Protein Dynamics and Electronic Structure

Proteins undergo conformational fluctuations on a range of time scales. Our group is investigating how protein structure modulates dynamics, and how dynamics impact function. One area that we have investigated in detail is the impact of polypeptide dynamics on heme conformation and electronic structure. We have found that polypeptide dynamics and heme dynamics are coupled to each other. In addition, polypeptide mobility impacts heme conformation and axial ligation, and thus heme electronic structure. 

Cytochrome c Folding

Protein folding is characterized by a large degree of heterogeneity. We are working toward characterizing the complex process of protein folding in terms of conformational and mechanistic complexity. Conformational changes of cytochrome c are of biological interest because of the relevance to its role in apoptosis.