Date of Award
College of Natural Science and Mathematics, Chemistry and Biochemistry
John Alexander Huffman
Air pollution, Nitration, Oligomerization, Oxidative stress, Ozone, Peroxynitrite
Proteins can react with reactive oxygen species (ROS) and reactive nitrogen species (RNS) to form post-translational modifications (PTMs), which can affect protein structure and function. The formation of 3-nitrotyrosine (NTyr) and dityrosine (DiTyr) upon reaction of proteins with ROS/RNS are two common PTMs studied due to their stability and irreversibility, as well as their ability to enhance the allergenicity of pollen allergens upon formation. Many common techniques used to study the formation of these PTMs can reliably detect the PTMs but can only provide semi-quantitative information due to many assumptions and limitations. In Chapter 2 we present an analysis of the common methodologies used and provide analytical perspectives for improved quantification.
NTyr can form via the reaction of proteins and urban air pollutants and may have implications in the increase in allergic disease seen worldwide. The reaction of proteins with ozone and nitrogen dioxide has been previously studied in controlled laboratory studies, but not extensively in urban air. In Chapter 3 we develop and characterize a method for the exposure of proteins to urban air, analysis, and quantification of NTyr in samples after exposure. An extensive ambient study was further conducted (Chapter 4) and the nitration degree, or NTyr concentration, of the exposed samples was correlated with air pollutant concentrations and atmospheric conditions. The formation of DiTyr in the exposed samples was also detected in this study, representing the first time the detection of oligomerization of proteins was reported in ambient air.
The reactions of proteins with endogenous ROS/RNS upon inhalation may be a further mechanism for the increase in allergenicity seen. Peroxynitrite (ONOO-) is an endogenous ROS formed under oxidative stress conditions. Here we show how using ONOO- in vitro to mimic oxidative stress in vivo has experimental artifacts, like an increase in pH that alters the reaction mechanism (Chapter 5), as well as how it reacts site-selectively with lactoferrin (Chapter 6). The studies shown provide information to tie together the nitration reactions occurring both in urban air and endogenously, which is imperative to determining the role each play in the increase in allergic disease.
Copyright is held by the author. User is responsible for all copyright compliance.
Rachel Lauren Davey
Received from ProQuest
Davey, Rachel Lauren, "Post-Translational Modification of Proteins via Ambient Air Pollutants and Endogenous Reactive Species" (2023). Electronic Theses and Dissertations. 2249.
Analytical chemistry, Biochemistry, Chemistry
Available for download on Thursday, August 01, 2024