Generating dihydrogen by tethering an [FeFe]hydrogenase via a molecular wire to the A1A/A1B sites of photosystem I
Photosystem I complexes from the menB deletion mutant of Synechocystis sp. PCC 6803 were previously wired to a Pt nanoparticle via a molecular wire consisting of 15-(3-methyl-1,4-naphthoquinone-2-yl)]pentadecyl sulfide. In the presence of a sacrificial electron donor and an electron transport mediator, the PS I-NQ(CH2)15S-Pt nanoconstruct generated dihydrogen at a rate of 44.3 µmol of H2 mg Chl−1 h−1 during illumination at pH 8.3. The menB deletion strain contains an interruption in the biosynthetic pathway of phylloquinone, which results in the presence of a displaceable plastoquinone-9 in the A1A/A1B sites. The synthesized quinone contains a headgroup identical to the native phylloquinone along with a 15-carbon long tail that is terminated in a thiol. The thiol on the molecular wire is used to bind the Pt nanoparticle. In this short communication, we replaced the Pt nanoparticle with an [FeFe]H2ase variant from Clostridium acetobutylicum that contains an exposed iron on the distal [4Fe-4S] cluster afforded by mutating the surface exposed Cys97 residue to Gly. The thiol on the molecular wire is then used to coordinate the corner iron atom of the iron–sulfur cluster. When all three components are combined and illuminated in the presence of a sacrificial electron donor and an electron transport mediator, the PSI-NQ(CH2)15S-[FeFe]H2ase nanoconstruct generated dihydrogen at a rate of 50.3 ± 9.96 μmol of H2 mg Chl−1 h−1 during illumination at pH 8.3. This successful in vitro experiment sets the stage for assembling a PSI-NQ(CH2)15S-[FeFe]H2ase nanoconstruct in vivo in the menB mutant of Synechocystis sp. PCC 6803.
This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s11120-019-00685-y
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Work Title | Generating dihydrogen by tethering an [FeFe]hydrogenase via a molecular wire to the A1A/A1B sites of photosystem I |
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License | In Copyright (Rights Reserved) |
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Publication Date | October 31, 2019 |
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Deposited | January 22, 2024 |
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