Light-induced protein nitration and degradation with HONO emission

Abstract

Abstract. Proteins can be nitrated by air pollutants (NO 2 ), enhancing their allergenic potential. This work provides insight into protein nitration and subsequent decomposition in the presence of solar radiation. We also investigated lightinduced formation of nitrous acid (HONO) from protein surfaces that were nitrated either online with instantaneous gas-phase exposure to NO 2 or offline by an efficient nitration agent (tetranitromethane, TNM). Bovine serum albumin (BSA) and ovalbumin (OVA) were used as model substances for proteins. Nitration degrees of about 1 % were derived applying NO 2 concentrations of 100 ppb under VIS/UV illuminated conditions, while simultaneous decomposition of (nitrated) proteins was also found during long-term (20 h) irradiation exposure. Measurements of gas exchange on TNMnitrated proteins revealed that HONO can be formed and released even without contribution of instantaneous heterogeneous NO 2 conversion. NO 2 exposure was found to increase HONO emissions substantially. In particular, a strong dependence of HONO emissions on light intensity, relative humidity, NO 2 concentrations and the applied coating thickness was found. The 20 h long-term studies revealed sustained HONO formation, even when concentrations of the intact (nitrated) proteins were too low to be detected after the gas exchange measurements. A reaction mechanism for the NO 2 conversion based on the Langmuir-Hinshelwood kinetics is proposed.

Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

“…Light can activate some of these surfaces (humic acid, proteins and other organic compounds, titanium dioxide, soot), which enhances NO 2 uptake and HONO production (George et al, 2005;Langridge et al, 2009;Monge et al, 2010;Ndour et al, 2008;Ramazan et al, 2004;Stemmler et al, 2007;Kebede et al, 2013;Meusel et al, 2017). However, NO 2 uptake coefficients and the ambient aerosol surface areas for heterogeneous reactions of NO 2 were nevertheless frequently found to be too low to account for the observed HONO production rates (Stemmler et al, 2007;Sarwar et al, 2008;Zhang et al, 2016).…”

“…humic acid, minerals, proteins and organically coated particles (Ammann et al, 1998;Arens et al, 2001;Aubin et al, 2007;Bröske et al, 2003;Han et al, 2016;Kalberer et al, 1999;Kleffmann et al, 1999;Kleffmann and Wiesen, 2005;Lelièvre et al, 2004;Kinugawa et al, 2011;Liu et al, 2015;Wang et al, 2003;Yabushita et al, 2009;Meusel et al, 2017). Light can activate some of these surfaces (humic acid, proteins and other organic compounds, titanium dioxide, soot), which enhances NO 2 uptake and HONO production (George et al, 2005;Langridge et al, 2009;Monge et al, 2010;Ndour et al, 2008;Ramazan et al, 2004;Stemmler et al, 2007;Kebede et al, 2013;Meusel et al, 2017).…”

Surface Deposition on Titania in a Physiological Solution with Ultraviolet Irradiation In Situ and Effect of Heat Treatment

“…Yamamoto [30] has reported the cell adsorption capacity of an organosilane monolayer covered by serum albumin after UV light degradation is increased. Release of nitrite was demonstrated in the procedure of protein nitration under solar radiation by Meusel [31] when BSA and ovalbumin were used as model proteins. Nitrite presence further facilitates the oxidation of proteins and accelerates the photodegradation of BSA [32,33].…”

Relative importance of gas uptake on aerosol and ground surfaces characterized by equivalent uptake coefficients

“…Ambient on-line measurements of γ eff will favor the model parameterization and improve our understanding of the multiphase processes within PBL in the real world (Li et al, 2019). Moreover, more gaseous and aerosol species such as VOCs and bioaerosols should also be investigated (Zhou et al, 1996;Wagner et al, 2002;Fried et al, 2003;Beck et al, 2013;Li et al, 2014;Ouyang et al, 2016;Liu et al 2017;Meusel et al 2017).…”