Chemical Modification of Proteins by Reactive Oxygen and Nitrogen Species under Atmospheric and Physiological Conditions

Reactive oxygen and nitrogen species (ROS/RNS) play important roles in the adverse health effects of air pollution and are produced in a wide range of atmospheric and physiological processes. The ROS/RNS can react with amino acids like tyrosine, leading to the formation of nitrotyrosine, dityrosine, and protein oligomers. These post-translational modifications can alter the immunological properties of the proteins, but the underlying molecular mechanisms, kinetics, and effects of such modifications have not yet been fully resolved. Over the past years, the reactions of various model proteins (bovine serum albumin, food and airborne allergens, disease-related proteins) with ozone (O₃), nitrogen dioxide (^•NO₂), and peroxynitrite were investigated for a wide range of reaction conditions. Here, we summarize key findings related to the nitration and oligomerization of proteins by atmospherically and physiologically relevant ROS/RNS and resulting effects on the TLR4 signaling and immune responses of chemically modified proteins.