title: Nitration of the birch pollen allergen Bet v 1.0101: efficiency and site-selectivity of liquid and gaseous nitrating agents.
abstract: Nitration of the major birch pollen allergen Bet v 1 alters the immune responses toward this protein, but the underlying chemical mechanisms are not yet understood. Here we address the efficiency and site-selectivity of the nitration reaction of recombinant protein samples of Bet v 1.0101 with different nitrating agents relevant for laboratory investigations (tetranitromethane, TNM), for physiological processes (peroxynitrite, ONOO(-)), and for the health effects of environmental pollutants (nitrogen dioxide and ozone, O₃/NO₂). We determined the total tyrosine nitration degrees (ND) and the NDs of individual tyrosine residues (NDY). High-performance liquid chromatography coupled to diode array detection and HPLC coupled to high-resolution mass spectrometry analysis of intact proteins, HPLC coupled to tandem mass spectrometry analysis of tryptic peptides, and amino acid analysis of hydrolyzed samples were performed. The preferred reaction sites were tyrosine residues at the following positions in the polypeptide chain: Y83 and Y81 for TNM, Y150 for ONOO(-), and Y83 and Y158 for O₃/NO₂. The tyrosine residues Y83 and Y81 are located in a hydrophobic cavity, while Y150 and Y158 are located in solvent-accessible and flexible structures of the C-terminal region. The heterogeneous reaction with O₃/NO₂ was found to be strongly dependent on the phase state of the protein. Nitration rates were about one order of magnitude higher for aqueous protein solutions (∼20% per day) than for protein filter samples (∼2% per day). Overall, our findings show that the kinetics and site-selectivity of nitration strongly depend on the nitrating agent and reaction conditions, which may also affect the biological function and adverse health effects of the nitrated protein.
authors: Multiphase Chemistry and Biogeochemistry Departments, Max Planck Institute for Chemistry , Hahn-Meitner Weg 1, 55128 Mainz, Germany.
authors: Kathrin
authors: K
authors: Reinmuth-Selzle
authors: Chloé
authors: C
authors: Ackaert
authors: Christopher J
authors: CJ
authors: Kampf
authors: Martin
authors: M
authors: Samonig
authors: Manabu
authors: M
authors: Shiraiwa
authors: Stefan
authors: S
authors: Kofler
authors: Hong
authors: H
authors: Yang
authors: Gabriele
authors: G
authors: Gadermaier
authors: Hans
authors: H
authors: Brandstetter
authors: Christian G
authors: CG
authors: Huber
authors: Albert
authors: A
authors: Duschl
authors: Gertie J
authors: GJ
authors: Oostingh
authors: Ulrich
authors: U
authors: Pöschl
mesh_terms: D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry* / Q000235:genetics; D029662:Betula / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009585:Nitrogen Dioxide / Q000737:chemistry; D010126:Ozone / Q000737:chemistry; D010455:Peptides / Q000032:analysis*; D030421:Peroxynitrous Acid / Q000737:chemistry; D011058:Pollen / Q000737:chemistry; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013774:Tetranitromethane / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D052179:Antigens, Plant; D010455:Peptides; D011994:Recombinant Proteins; C061312:Bet v 1 allergen, Betula; D030421:Peroxynitrous Acid; D014443:Tyrosine; D010126:Ozone; D013774:Tetranitromethane; D009585:Nitrogen Dioxide