• Optimize biotinylation reaction conditions• Functionalize PSII with biotin on the stromal-side• Co-assemble the biotinylated PSI and PSII onto streptavidin-

coated gold particles

• Perform oxygen and hydrogen evolution assays for PSI/PSII-AuNP conjugates

Conclusions

Oriented Interface of PSI and PSII for Solar Driven Hydrogen EvolutionAlexandra Quiñones-Meléndez1, Evan A. Gizzie2, Chris Stachurski2, G. Kane Jennings3 and David E. Cliffel2

1Department of Chemical Engineering, University of Puerto Rico at Mayaguez, PR 006802Department of Chemistry, Vanderbilt University, Nashville, TN 37235

3Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235

Photosystem I (PSI) and Photosystem II (PSII) carry out photosynthesis in green plants. PSI has hydrogen reduction abilities, and PSII has water splitting power.

Hydrogen is a strong contender as a next generation clean and green fuel. What if photosynthesis became our hydrogen source?

Results

Thanks to the Cliffel Research Group especially to Evan A. Gizzie, Chris Stachurski, and Dilek Dervishogullari for their

collaboration.

Hydrogen Evolution Role of Photosystems I and II

Objectives

PSI Extraction

Interface PSI and PSII together in a head-to-tail fashion tosustainably generate H2 and O2 from sunlight and water:

• Functionalize PSI with biotin on the luminal-side

• Functionalize PSII with biotin on the stromal-side

• Co-assemble on gold nanoparticle

PSI is extracted from spinach

Methodology

Stromal-side Passivation of PSI

N N

N𝑁𝐻2 𝑁𝐻2

𝑁𝐻2

Sulfo-NHS-Acetate

Native Photosystem I Acetylated Photosystem I

HO

Acetylated Photosystem I

Biotin

Biotinylated Photosystem I

N N

N

PSII PSI

PSI has been functionalizedon its luminal side, allowingfor oriented deposition onstreptavidin functionalizedgold nanoparticles.

0

300

600

900

480 520 560 600

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

Native PSI

Acetylated PSI

Biotinylated PSI

Biotinylation of Photosystem I was determined spectrophotometrically usingFluorescein Isothiocyanate (FITC), which reacts with primary amines.

Luminal-side Biotinylation of PSI

N N

N

𝑁𝐻2 𝑁𝐻2 𝑁𝐻2

88

3622

0

40

80

NativePSI

AcetylatedPSI

BiotinylatedPSI

Lysi

ne

/PSI

Rat

io

SDS-PAGE Analysis Fluorescein Spectroscopy

Acknowledgements

Add Sulfo-NHS-Acetate

Introduction

We will integrate these two proteins into a single “wired” assembly for simultaneous water splitting and H2 generation.

PSI and PSII Assembly

Grinding buffer

Cheese cloth

Centrifuge

Discard

Re-suspended with buffer and discard supernatant (3x)

Re-suspended with buffer and 1% surfactant (3x)

Discard

CentrifugeCentrifuge

Dialysis

Stromal side

Luminal side

We gratefully acknowledge financial support from the National Science Foundation (Grant No: 1560414), in collaboration with

Vanderbilt Institute of Nanoscale Science and Engineering (VINSE)

References

Future Directions

[1] Ciesielski, P. N., Cliffel, D. E., & Jennings, G. K. (2011). Kinetic model of the photocatalytic effect of a photosystem I monolayer on a planar electrode surface. Journal of Physical Chemistry A, 115(15), 3326–3334.

[2] Utschig, L. M., Silver, S. C., Mulfort, K. L., & Tiede, D. M. (2011). Nature-Driven Photochemistry for Catalytic Solar Hydrogen, 16334–16337.

[3] LeBlanc, G., Gizzie, E., Yang, S., Cliffel, D. E., & Jennings, G. K. (2014). Photosystem I protein films at electrode surfaces for solar energy conversion. Langmuir, 30(37), 10990–1001. http://doi.org/10.1021/la500129q

4

7

16

34

55

78

105

PsaA/PsaB

PsaD/PsaF/PsaL

Psa/PsaJ

PsaC

BiotinBiotin

Biotin

Biological Science, Copyright 2005, Pearson Benjamin Cummings

[3] LeBlanc, Langmuir, 30(37), 10990–1001.