Radiation and Dehydration Resistance of Proteins

Louisiana State University, Baton Rouge LA

Investigators

Abstract

This research will determine the resistance of individual proteins to radiation and dehydration, in order to understand how these properties evolve at the molecular level, and to provide long-range guidance for designing radiation and dehydration resistance into proteins. Radiation and dehydration are both forces that damage biological systems. They are related to each other because both induce the production of free radicals, which are extremely destructive chemical species. Understanding how proteins may have evolved to resist free radical damage adds to the fundamental understanding of the spectrum of protein properties and capabilities, and has potential long-range impacts for food production, bioengineering, bioremediation, and green chemistry. Conduct of this research will result in the training of undergraduate and graduate students, as well as postdoctoral researchers, in a broad array of biophysical techniques and quantitative analytical methods. This project also includes development of novel science outreach and public engagement activities, including educational based performances and presentations for general audiences that are designed to communicate the science of biochemistry under extreme environmental conditions. This project specifically examines a suite of DNA binding proteins from the bacterium Deinococcus radiodurans in direct comparison with the homologous proteins from Escherichia coli. D. radiodurans is one of the most radiation resistant organisms on Earth, surviving radiation doses 2,000 times greater than those that would kill humans or E. coli. By directly examining the function and stability of the irradiated isolated proteins from this radiation resistant organism alongside the equivalent, homologous proteins from a radiation sensitive organism, the project will answer the question of whether intrinsic radiation resistance is an evolvable protein property in the same way that some proteins have evolved to be heat resistant, acid resistant, or salt resistant. The paired proteins will be examined under increasing exposure to radiation, UV light, and dehydration for differential effects on their DNA binding affinity, protein folding and stability, enzymatic activity, and affinity for antioxidants. Because this project examines protein function and stability, it does not simply ask if radiation induced free radicals damage some proteins less frequently than others, it asks if the primary physiological activities (i.e. the important functional parts) of some species of proteins are less susceptible to radiation damage than others, and how that difference originates.