Constrained synthesis and organization of catalytically active metal nanoparticles by self-assem bled protein templates

Constrained synthesis and organization of catalytically active metal nanoparticles by self-assembled protein templates is analyzed. The protein has an extremely high thermal and chemical stability. When the 6hisSP1 mutant was treated with Na₂PdCl₄ for 2h at room temperature, a homogenous pale-yellow solution resulted. The particulate texture and size suggest that the wild-type template also influences initial particle nucleation. However, binding of the particles to the protein seems to be weak, and the particles, once formed, are released and precipitate from the solution. The initial UV-vis spectrum revealed two very small shoulders, corresponding to tryptophanes and tyrosines at 280 nm and 290 nm and to the palladium/protein complex at 340 nm, respectively. SDS-polyacrylamide gel electrophoresis (PAGE) analysis of Pd-6hisSP1 after reduction, demonstrated that the protein maintained its original characteristics and the dodecamerica structure as expected.