title: Solar hydrogen-producing bionanodevice outperforms natural photosynthesis.
abstract: 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. On illumination, the PSI-[FeFe]-H(2)ase nanoconstruct evolves H(2) at a rate of 2,200 ± 460 μmol mg chlorophyll(-1) h(-1), which is equivalent to 105 ± 22 e(-)PSI(-1) s(-1). Cyanobacteria evolve O(2) at a rate of approximately 400 μmol mg chlorophyll(-1) h(-1), which is equivalent to 47 e(-)PSI(-1) s(-1), given a PSI to photosystem II ratio of 1.8. The greater than twofold electron throughput by this hybrid biological/organic nanoconstruct over in vivo oxygenic photosynthesis validates the concept of tethering proteins through their redox cofactors to overcome diffusion-based rate limitations on electron transfer.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Lubner
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Applegate
authors.forename: Philipp
authors.initials: P
authors.lastname: Knörzer
authors.forename: Alexander
authors.initials: A
authors.lastname: Ganago
authors.forename: Donald A
authors.initials: DA
authors.lastname: Bryant
authors.forename: Thomas
authors.initials: T
authors.lastname: Happe
authors.forename: John H
authors.initials: JH
authors.lastname: Golbeck
mesh_terms: D046969:Clostridium acetobutylicum / Q000378:metabolism*; D004579:Electron Transport; D006859:Hydrogen / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods*; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000378:metabolism; D012993:Solar Energy; D013057:Spectrum Analysis; D046940:Synechococcus / Q000378:metabolism*
chemical_list: D045331:Photosystem I Protein Complex; D006859:Hydrogen; D007501:Iron