Journal
PHOTOSYNTHESIS RESEARCH
Volume 128, Issue 1, Pages 45-57Publisher
SPRINGER
DOI: 10.1007/s11120-015-0198-6
Keywords
Ferredoxin; Chlamydomonas; Structure; Interaction; NADPH; Hydrogen photo-production
Categories
Funding
- U. S. Department of Energy, Office of Biological and Environmental Research (BER)
- U. S. Department of Energy Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences for EPR spectroscopy
- Office of Energy Efficiency and Renewable Energy
- Bioenergy Technology Office (BETO)
Ask authors/readers for more resources
The green alga Chlamydomonas reinhardtii contains six plastidic [2Fe2S]-cluster ferredoxins (FDXs), with FDX1 as the predominant isoform under photoautotrophic growth. FDX2 is highly similar to FDX1 and has been shown to interact with specific enzymes (such as nitrite reductase), as well as to share interactors with FDX1, such as the hydrogenases (HYDA), ferredoxin:NAD(P) reductase I (FNR1), and pyruvate:ferredoxin oxidoreductase (PFR1), albeit performing at low catalytic rates. Here we report the FDX2 crystal structure solved at 1.18 resolution. Based on differences between the Chlorella fusca FDX1 and C. reinhardtii FDX2 structures, we generated and purified point-mutated versions of the FDX2 protein and assayed them in vitro for their ability to catalyze hydrogen and NADPH photo-production. The data show that structural differences at two amino acid positions contribute to functional differences between FDX1 and FDX2, suggesting that FDX2 might have evolved from FDX1 toward a different physiological role in the cell. Moreover, we demonstrate that the mutations affect both the midpoint potentials of the FDX and kinetics of the FNR reaction, possibly due to altered binding between FDX and FNR. An effect on H-2 photo-production rates was also observed, although the kinetics of the reaction were not further characterized.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available