Solar hydrogen-producing bionanodevice outperforms natural photosynthesis.

Although a number of solar biohydrogen systems employing photosystem I (PSI) have been developed, few attain the electron transfer throughput of oxygenic photosynthesis. We have optimized a biological/organic nanoconstruct that directly tethers F(B), the terminal [4Fe-4S] cluster of PSI from Synechococcus sp. PCC 7002, to the distal [4Fe-4S] cluster of the [FeFe]-hydrogenase (H(2)ase) from Clostridium acetobutylicum.

The cysteine-proximal aspartates in the Fx-binding niche of photosystem I. Effect of alanine and lysine replacements on photoautotrophic growth, electron transfer rates, single-turnover flash efficiency, and EPR spectral properties.

The FX electron acceptor in Photosystem I (PS I) is a highly electronegative (Em = -705 mV) interpolypeptide [4Fe-4S] cluster ligated by cysteines 556 and 565 on PsaB and cysteines 574 and 583 on PsaA in Synechocystis sp. PCC 6803. An aspartic acid is adjacent to each of these cysteines on PsaB and adjacent to the proline-proximal cysteine on PsaA.

Dynamics of the excited state of the primary electron donor in reaction centers of Rhodopseudomonas viridis as revealed by hole burning at 1.7K. Different conformational states.

The spectra of absorbance changes (delta A) due to the formation of P+Q- (P, primary electron donor, Q, primary quinone acceptor) at 1.7K in Rhodopseudomonas viridis reaction centers (RCs) excited at 1014 nm has been shown to include, besides a progression of broad (170-190 cm-1) Gaussian vibronic bands separated by 150 cm-1, a 'narrow' structure near 1014 nm which can be simulated by a Lorentian zero-phonon hole (ZPH) and Lorentian one-mode (26.8 cm-1) phonon wings.

Sub-picosecond dynamics of excited state of primary electron donor in reaction centers of Rhodopseudomonas viridis as revealed by hole burning at 1.7K broad and narrow holes.

Within the QF band of the primary electron donor (P), the spectra of absorbance changes due to the formation of a state of P+QA- (QA is the primary quinone) at 1.7K in Rhodopseudomonas viridis reaction centers excited at 1014 nm have been shown to involve two spectral features characterized by: (i) a progression of broad (170-190 cm-1) Gaussian vibronic bands (S-factor = 1.4) separated by 150 cm-1 and (ii) a 'narrow' structure near 1014 nm, characterized by 0-0 transition at 1014 nm with a width of approximately 50 cm-1 and 0-1 transition at 1000 nm with the width of approximately 100 cm-1, and S-factor = 0.

Quantitative method for studying orientation of transition dipoles in membrane vesicles of spherical symmetry.

Pigmented vesicular membranes embedded in polyacrylamide gel exhibit linear dichroism when the gel sample is squeezed [Abdourakhmanov, I.A., Ganago, A.