 |
John H. GolbeckProfessor of Biochemistry and Biophysics 310 South Frear Laboratory, University Park, PA 16802 B.S. in Chemistry from Valparaiso University Golbeck Lab Web Site |
| Home | Research | Teaching | Publications | Lab Personnel | Collaborators | Links | Societies |
Research in Photosynthesis |
|
Sunlight is the ultimate
source of energy for most organisms on Earth. In plants, algae and cyanobacteria,
the energy of light is used to synthesize carbohydrates from CO2,
resulting in the byproduct of atmospheric O2.
My research group focuses on the study of Type I (iron-sulfur) reaction
centers, including Photosystem I of cyanobacteria (Figure 1.1)
and plants, and the reaction centers of the strictly anaerobic heliobacteria
and green sulfur bacteria. My students and I work to uncover the genes,
polypeptides, and cofactors that are involved in the structure, function,
and assembly of Type I reaction centers. To accomplish these goals, we
employ molecular biological techniques such as site-directed mutagenesis
and secondary suppressor screening, biochemical techniques such as resolution
and reconstitution of proteins and cofactors, and biophysical techniques
such as magnetic resonance spectroscopy and time-resolved optical spectroscopy. |
 |
| Figure 1.1. View form the stromal surface of the Photosytem I trimer from Thermosynechococcus elongatus. Figure from P. Jordan, Ph.D. thesis, Berlin. | |
Why Study Photosynthesis? |
|
The world’s dependence on fossil fuels for energy is fraught with a variety of environmental, social and political problems. Looming over the horizon is the eventual depletion of the inexpensive oil and natural gas that currently powers the world’s economy. The already-noticeable onset of global warming caused by the build-up of atmospheric carbon dioxide and methane threatens the world’s climate (Figure 1.2). The solution to the energy problem is to construct an economy based on hydrogen as a primary fuel. Unlike the combustion of fossil fuels, which produces carbon dioxide, the combustion of hydrogen produces only water as byproduct. |
 Figure 1.2. The green color depicts the portion of the Earth's land surface that supports oxygenic photosynthesis. |
The trick is to synthesize hydrogen
without using fossil fuels as an intermediate; i.e. directly
with the use of solar, wind or tidal power. The product of Photosystem
I is NADPH, a molecule with about the same standard free energy of combustion
as hydrogen. Work in my laboratory is aimed ultimately at modifying
the acceptor system of Photosystem I so that the product is H2 rather
than the biological reductant NADPH. |
|
If you would like to learn more about
the light reactions of photosynthesis and especially Photosystem I, I
have written a chapter called “Photosynthetic Electron Transfer:
So Little Time, So Much to Do” for ‘Biophysics Textbook On
Line. You can download the chapter at: http://www.biophysics.org/btol/ or download the pdf file here. |
|
Search the MEDLINE database at PubMed for articles by J Golbeck