Evaluation of the photosynthetic reaction center protein for potential use as a bioelectronic circuit element.

The characterization of a bioelectronic composite prepared by molecular wiring of a bacterial photosynthetic reaction center (RC) to a metal (Au) electrode is described. Two unique attachment sites on the protein surface were studied as sites for electrical connections--a polyhistidine tag introduced by site-directed mutagenesis and a native cysteine amino acid residue. These two attachment sites were evaluated independently and found to serve effectively in coupling the protein to the electrode surface asymmetrically.

Virus-based toolkit for the directed synthesis of magnetic and semiconducting nanowires.

We report a virus-based scaffold for the synthesis of single-crystal ZnS, CdS, and freestanding chemically ordered CoPt and FePt nanowires, with the means of modifying substrate specificity through standard biological methods. Peptides (selected through an evolutionary screening process) that exhibit control of composition, size, and phase during nanoparticle nucleation have been expressed on the highly ordered filamentous capsid of the M13 bacteriophage. The incorporation of specific, nucleating peptides into the generic scaffold of the M13 coat structure provides a viable template for the directed synthesis of semiconducting and magnetic materials.

Anticipatory evolution and DNA shuffling.

DNA shuffling has proven to be a powerful technique for the directed evolution of proteins. A mix of theoretical and applied research has now provided insights into how recombination can be guided to more efficiently generate proteins and even organisms with altered functions.