Training Group:

Plant Biology

Mentor / Lab:

Sujith Puthiyaveetil

Specific Research Area / Project:

Photosynthetic Electron Transport/Phosphorylation in Photosystem II Repair Cycle

Research Profile:

Photosynthesis is a light-driven process that is responsible for generation of usable forms of chemical energy in plants, algae, and cyanobacteria. Photosynthetic electron transport uses the ubiquitously available energy from light to perform several complex redox reactions, driving the formation of the "energy currency" ATP and the reductant NADPH. These reactions are catalyzed by several large hetero-oligomeric protein complexes, including the spectrally distinct photosystems (Photosystem I and II), cytochrome b6f, and ATP Synthase. Photosystem II (PSII) has the unique enzymatic activity of oxidizing water into elemental oxygen and protons while liberating electrons for the electron transport chain. Although the "water-splitting" reaction catalyzed by PSII is necessary for photosynthesis, it does irreversible oxidative damage to several residues of the PSII reaction center. To deal with this constant photodamage, PSII undergoes a poorly understood disassembly and repair process that results in a fully functional PSII.

My research focuses on the roles of post-translational modifications (PTM) in the disassembly and repair of PSII supercomplexes. Photosystem II is composed of four core subunits surrounded by monomeric and trimeric light-harvesting antenna proteins in several biogenic and disassembly intermediates. Phosphorylation of the core subunits of PSII seems to be important for the disassembly and repair of PSII supercomplexes. However, the mechanism by which phosphorylation drives this process is not clear. My research uses biochemical, spectroscopic, and proteomic techniques to identify the roles of PTMs in the PSII repair cycle using the model plant Arabidopsis thaliana.

About Me:

I grew up on a rural farm in Michigan, so I had always been interested in plants and genetically modified crops. From that curiosity, I became interested in the genetic and molecular mechanisms that controlled plant growth and development, and went on to pursue my BS in Cell and Molecular Biology at Grand Valley State University. During my time at GVSU, I gained research experience in a plant research lab, and decided to further pursue a PhD in plant science.

My experience in PULSe has been great. The first year rotation program allowed me to explore my options at Purdue, and to gain a better understanding for the research opportunities and facilities available here. PULSe has allowed me to take a curriculum that matched my research interests, which has been really beneficial to my research progress. One of my favorite experiences has been the weekly departmental seminars, which are a good opportunity to hear interesting talks and learn about ongoing research in the department.

Ultimately, I would like to run my own research lab in the future. I enjoy doing independent research and would like to be in a position where I can make more independent research decisions in the future.

Awards:

• Lynn Fellowship (2018)

Publications:

• McKenzie SD, Ibrahim IM, Aryal UK, Puthiyaveetil S. Stoichiometry of protein complexes in plant photosynthetic membranes. Biochim Biophys Acta - Bioenerg. 2020;1861(2). doi:10.1016/j.bbabio.2019.148141

Presentations:

• Steven D. McKenzie, Iskander M. Ibrahim, Uma K. Aryal, Sujith Puthiyaveetil. (March, 2020) Stoichiometry of electron transport complexes in plant photosynthetic membrane. Presented poster presentation at Biochemical Horizons Symposium, Purdue University, West Lafayette, IN.
• Steven D. McKenzie. Regulation of Complex Disassembly by Core Phosphorylation In the PSII Repair Cycle. (November, 2019) Presented oral presentation at Purdue Department of Biochemistry Grad Student/Postdoc Seminar, Purdue University, West Lafayette, IN.
• Steven D. McKenzie, Iskander M. Ibrahim, Uma K. Aryal, Sujith Puthiyaveetil. (October, 2019) Stoichiometry of electron transport complexes in plant photosynthetic membrane. Presented oral presentation at Midwest/Southeast Photosynthesis Conference, Turkey Run State Park, IN.
• Steven D. McKenzie, Iskander M. Ibrahim, Uma K. Aryal, Sujith Puthiyaveetil. (August, 2019) Determination of Photosynthetic Electron Transport Complex Stoichiometries by LC-MS/MS. Presented lightning talk at Purdue Department of Biochemistry Retreat, Purdue University, West Lafayette, IN.
• Steven D. McKenzie, Gyeong Mee Yoon. (April, 2019) Cloning Intein-2A Coexpression Cassette for Quantifying Protein Turnover in Arabidopsis thaliana. Presented poster presentation at PULSe First Year Rotation Poster Session, Purdue University, West Lafayette, IN.
• Steven D. McKenzie, Matthew J. Christians. (April, 2018) Analysis of COP9 Signalosome Mutants Reveals a Role of the CSN in Ethylene Sensitivity in Arabidopsis thaliana. Annual GVSU Cell and Molecular Biology Undergraduate Research Symosium, Grand Valley State University, Allendale, MI.
• Steven D. McKenzie, Matthew J. Christians. (March, 2018) Analysis of COP9 Signalosome Mutants Reveals a Role of the CSN in Ethylene Sensitivity in Arabidopsis thaliana. Presented at poster presentation at American Society of Plant Biologists Midwest Section Meeting, Iowa State University, Ames, IA.
• Steven D. McKenzie, Matthew J. Christians. (November, 2017) Ethylene Induced Modification of EIN2 C-Terminus in Arabidopsis thaliana. Presented at poster presentation at West Michigan Regional Undergraduate Science Research Conference, Van Andel Institute, Grand Rapids, MI.
• Steven D. McKenzie, Matthew J. Christians. (March, 2017) Ethylene Induced Modification of EIN2 C-Terminus in Arabidopsis thaliana. Presented at poster presentation at Grand Valley State University Student Scholars Day, Grand Valley State University, Allendale, MI.