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Sujith Puthiyaveetil


  • Assistant Professor of Biochemistry
BCHM Room 305A

 General Information

Area of Expertise: Genetic and molecular control of photosynthetic light utilization 

The properties of light baffle even the smartest physicist. Born in the nuclear fusion reactions of the sun and behaving as both a particle and wave simultaneously, light travels through space and reaches earth. Plants, algae, and certain bacteria tap into this mysterious source of energy through the process of photosynthesis to power themselves and others who depend on them for energy. Light photons in the visible range pack enough punch to knock electrons off chlorophyll molecules and set the electron transport reactions of photosynthesis in motion, which produce NADPH, the reducing power, and an electrochemical potential that drives the synthesis of ATP. The energy rich molecules formed during the light reactions are expended in the carbon fixation reactions of photosynthesis, which convert carbon dioxide into carbohydrates. Complex life on earth is the exploit of this remarkable chemical reaction.

Seemingly abundant for photosynthesis, sunlight however varies profoundly in its quality and quantity on a timescale of seconds to seasons. This heterogeneity in the supply of light poses particular challenges for the photosynthetic machinery. Our laboratory studies the genetic and molecular control mechanisms plants and algae employ, under some conditions, to make use of every photon that is available for photosynthesis, whilst in others to protect the photosynthetic machinery from excess light. Of particular interest is the function and evolution of an ancient gene regulatory circuit known as the chloroplast two-component system. In plants and green algae, the chloroplast two-component system has been rewired in evolution to assume novel light acclimation and signaling properties. A complete understanding of modified and canonical chloroplast two-component systems will reveal the crucial link between photosynthesis, gene expression, and the biogenesis of electron transport complexes.

In plants and green algae, a pair of conserved serine/threonine protein kinases phosphorylate photosystem II (PS II), the water-splitting photosystem of oxygenic photosynthesis, in a light quality and quantity-dependent manner. One substrate of PS II protein kinases is Light Harvesting Complex II (LHC II), the most prolific light harvesting antenna protein on earth. LHC II phosphorylation redistributes absorbed excitation energy between the two photosystems through a remarkable light quality acclimatory response known as state transitions. The phosphorylation of PS II core proteins facilitates the turnover of damaged photosystems through PS II repair cycle, one of the most efficient protein repair mechanism found in nature. A major goal of our laboratory is to understand the precise regulatory and functional mechanisms by which PS II protein kinase drive state transitions and PS II repair cycle. We use the model higher plant Arabidopsis thaliana and the model diatom Phaeodactylum tricornutum as experimental systems, employing biochemical, biophysical, and functional genomics tools.   

Department of Biochemistry, 175 South University Street, West Lafayette, IN 47907-2063 USA, (765) 494-1600

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