Self-assembling light-harvesting systems from synthetically modified Tobacco mosaic virus coat proteins

ORGN 278

Rebekah A. Miller, rmiller@berkeley.edu, Andrew D. Presley, apresley@berkeley.edu, and Matthew B. Francis, francis@cchem.berkeley.edu. Department of Chemistry, University of California, Berkeley, 727 Latimer Hall, Berkeley, CA 94720
A new protein-based approach has been developed for the construction of light harvesting systems through self-assembly. The building blocks were prepared by attaching fluorescent chromophores to cysteine residues introduced on tobacco mosaic virus coat protein monomers. When placed under the appropriate buffer conditions, these conjugates could be assembled into double-layer disks or into rods that reached hundreds of nanometers in length. Characterization of the system using fluorescence spectroscopy indicated that efficient energy transfer could be achieved from large numbers of donor chromophores to a single acceptor. Energy transfer across distances exceeding the Förster radius for a single donor-acceptor pair is proposed to occur through a series of degenerate donor-to-donor transfer events. Three-chromophore systems were also prepared to achieve broad spectrum light collection. Through the combination of self-organizing biological structures and synthetic building blocks, a highly tunable new method has emerged for the construction of photovoltaic device components.