Porous silicon/photosynthetic reaction center hybrid nanostructure.
The purified photosynthetic reaction center protein (RC) from Rhodobacter sphaeroides R-26 purple bacteria was bound to porous silicon microcavities (PSiMc) either through silane-glutaraldehyde (GTA) chemistry or via a noncovalent peptide cross-linker. The characteristic resonance mode in the microcavity reflectivity spectrum red shifted by several nanometers upon RC binding, indicating the protein infiltration into the porous silicon (PSi) photonic structure. Flash photolysis experiments confirmed the photochemical activity of RC after its binding to the solid substrate. The kinetic components of the intraprotein charge recombination were considerably faster (τ(fast) = 14 (±9) ms, τ(slow) = 230 (±28) ms with the RC bound through the GTA cross-linker and only τ(fast) = 27 (±3) ms through peptide coating) than in solution (τ(fast) = 120 (±3) ms, τ(slow) = 1387 (±2) ms), indicating the effect of the PSi surface on the light-induced electron transfer in the protein. The PSi/RC complex was found to oxidize the externally added electron donor, mammalian cytochrome c, and the cytochrome oxidation was blocked by the competitive RC inhibitor, terbutryne. This fact indicates that the specific surface binding sites on the PSi-bound RC are still accessible to external cofactors and an electronic interaction with redox components in the aqueous environment is possible. This new type of biophotonic material is considered to be an excellent model for new generation applications at the interface of silicon-based electronics and biological redox systems designed by nature.
Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
Kata
K
Hajdu
Csilla
C
Gergely
Marta
M
Martin
Thierry
T
Cloitre
László
L
Zimányi
Katalin
K
Tenger
Petro
P
Khoroshyy
Gabriela
G
Palestino
Vivechana
V
Agarwal
Klára
K
Hernádi
Zoltán
Z
Németh
László
L
Nagy
D000818:Animals; D004579:Electron Transport; D049329:Nanostructures / Q000737:chemistry*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D016062:Porosity; D012242:Rhodobacter sphaeroides / Q000201:enzymology; D012825:Silicon / Q000737:chemistry*
D045322:Photosynthetic Reaction Center Complex Proteins; D012825:Silicon