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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Modulation Of Cyanobacterial Photosystem I Deposition Properties On Alkanethiolate Au Substrate By Various Experimental Conditions, Dibyendu Mukherjee, Michael Vaughn, Bamin Khomami, Barry Bruce Oct 2011

Modulation Of Cyanobacterial Photosystem I Deposition Properties On Alkanethiolate Au Substrate By Various Experimental Conditions, Dibyendu Mukherjee, Michael Vaughn, Bamin Khomami, Barry Bruce

Barry D. Bruce

We present results from atomic force microscopy (AFM) images indicating various experimental conditions, which alter the morphological characteristics of self-assembled cyanobacterial PS I on hydroxyl-terminated self-assembled alkanethiolate monolayers (SAM/Au) substrates. AFM topographical images of SAM/Au substrates incubated in solutions containing different PS I concentrations solubilized with Triton X-100 as the detergent reveal large columnar aggregates (∼100 nm and hence, much taller than a single PS I trimer) at high PS I concentrations. Depositions from dilute PS I suspensions reveal fewer aggregates and relatively uniform surface topography (∼10 nm). Confocal fluorescence microscopy analysis of fluorescently tagged PS I deposited ...


Optimization Of Photosynthetic Hydrogen Yield From Platinized Photosystem I Complexes Using Response Surface Methodology, Ifeyinwa Iwuchukwu, Ernest Iwuchukwu, Rosemary Le, Caitlin Paquet, Rapinder Sawhney, Barry Bruce, Paul Frymier Aug 2011

Optimization Of Photosynthetic Hydrogen Yield From Platinized Photosystem I Complexes Using Response Surface Methodology, Ifeyinwa Iwuchukwu, Ernest Iwuchukwu, Rosemary Le, Caitlin Paquet, Rapinder Sawhney, Barry Bruce, Paul Frymier

Barry D. Bruce

Light-dependent hydrogen production by platinized Photosystem I isolated from the cyanobacterium Thermosynechococcus elongatus BP-1 was optimized using response surface methodology (RSM). The process parameters studied included temperature, light intensity and wavelength, and platinum salt concentration. Application of RSM generated a model that agrees well with the data for H2 yield (R2 = 0.99 and p < 0.001). Significant effects on the total H2 yield were seen when the platinum salt concentration and temperature were varied during platinization. However, light intensity during platinization had a minimal effect on the total H2 yield within the region studied. The values of the parameters used during the platinization that optimized the production of H2 were light intensity of 240 μE m−2 s−1, platinum salt concentration of 636 μM and temperature of 31 °C. A subsequent validation experiment at the predicted conditions for optimal process yield gave the maximum H2 yield measured in the study, which was 8.02 μmol H2 per mg chlorophyll.


Protein Engineering For The Enhanced Photo-Production Of Hydrogen By Cyanobacterial Photosystem I, Ifeyinwa Jane Iwuchukwu May 2011

Protein Engineering For The Enhanced Photo-Production Of Hydrogen By Cyanobacterial Photosystem I, Ifeyinwa Jane Iwuchukwu

Doctoral Dissertations

Photosystem I (PSI) from plants, algae, and cyanobacteria can mediate H2 evolution in vivo and in vitro. A simple, self-platinization procedure that permits stable PSI-mediated H2 evolution in vitro has been developed. The H2 evolution capabilities of PSI from Thermosynechococcus elongatus have been characterized. This organism utilizes cytochrome c6 (cyt c6) as the e- donor to P700. Using a solution-based, self-organized platinization of the PSI nanoparticles, this study demonstrates a sodium ascorbate-cyt-PSI-Pt-H2 electron transport and proton reduction system that yields light-dependent H2. The system was thermostable with H2 evolution increasing up to 55°C. In addition, stability studies have shown ...