Kevin Hines
Kevin Hines
Faculty Advisor: Maureen Hanson
Year: 2012

Expression of the essential β-carboxysome protein, CcmN, in Nicotiana tabacum (tobacco) andNicotiana benthamiana

The carboxysome is a bacterial microcompartment found in the photosynthetic bacteria, cyanobacteria, which function in the carbon concentration mechanism (CCM). This structure concentrates CO2 around RuBisCO (the enzyme responsible for fixing CO2 in photosynthesis) and isolates O2 away from RuBisCO, thus preventing photorespiration. Photorespiration is a very costly process in plants that occurs when RuBisCO reacts with O2 and creates a product that must be degraded, therefore causing the plant to waste ATP and NADPH. This becomes a problem in C3 plants (wheat, rice, barley, etc.) when they close their stomata at high temperatures and build up internal O2 levels, resulting in reduced photosynthetic efficiency. The overall goal of the project is to engineer functional carboxysomes in the plant’s chloroplasts in order to reduce photorespiration and improve yields at higher temperatures. I worked with the carboxysome protein, CcmN, which is essential for the formation of the carboxysome structure by interacting with the major shell protein, CcmK2, and with CcmM (which interacts with RuBisCO). The correct interaction of proteins in the chloroplast is essential for the formation of the whole carboxysome. I designed vectors to express CcmN and to coexpress it with CcmM and CcmK2 to visualize its expression and structure in the chloroplasts of Nicotiana tabacum (tobacco) and Nicotiana benthamiana when expressed alone or with the other shell proteins.

My Experience

As a PGRP intern I had the chance to be at the forefront of modern plant biology. I was able to learn new skills and techniques from amazing scientists who guided me along my ten-week internship. I am certain that this experience will aid me as I begin to apply to graduate schools and work on my Ph.D. Though requiring a lot of work, both inside and outside the lab, this program has shown me how satisfying a scientific career can and will be.