title: Transmembrane nitration of hydrophobic tyrosyl peptides. Localization, characterization, mechanism of nitration, and biological implications.
abstract: We have shown previously that peroxynitrite-induced nitration of a hydrophobic tyrosyl probe is greater than that of tyrosine in the aqueous phase (Zhang, H., Joseph, J., Feix, J., Hogg, N., and Kalyanaraman, B. (2001) Biochemistry 40, 7675-7686). In this study, we have tested the hypothesis that the extent of tyrosine nitration depends on the intramembrane location of tyrosyl probes and on the nitrating species. To this end, we have synthesized membrane spanning 23-mer containing a single tyrosyl residue at positions 4, 8, and 12. The location of the tyrosine residues in the phospholipid membrane was determined by fluorescence and electron spin resonance techniques. Nitration was initiated by slow infusion of peroxynitrite, co-generated superoxide and nitric oxide ((.)NO), or a myeloperoxidase/hydrogen peroxide/nitrite anion (MPO/H(2)O(2)/NO(2)(-)) system. Results indicate that with slow infusion of peroxynitrite, nitration of transmembrane tyrosyl peptides was much higher (10-fold or more) than tyrosine nitration in aqueous phase. Peroxynitrite-dependent nitration of tyrosyl-containing peptides increased with increasing depth of the tyrosyl residue in the bilayer. In contrast, MPO/H(2)O(2)/ NO(2)(-)-induced tyrosyl nitration decreased with increasing depth of tyrosyl residues in the membrane. Transmembrane nitrations of tyrosyl-containing peptides induced by both peroxynitrite and MPO/H(2)O(2)/NO(2)(-) were totally inhibited by (.)NO that was slowly released from spermine NONOate. Nitration of peptides in both systems was concentration-dependently inhibited by unsaturated fatty acid. Concomitantly, an increase in lipid oxidation was detected. A mechanism involving (.)NO(2) radical is proposed for peroxynitrite and MPO/H(2)O(2)/NO(2)(-)-dependent transmembrane nitration reactions.
authors.affiliation: Biophysics Research Institute and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Kalpana
authors.initials: K
authors.lastname: Bhargava
authors.forename: Agnes
authors.initials: A
authors.lastname: Keszler
authors.forename: Jimmy
authors.initials: J
authors.lastname: Feix
authors.forename: Neil
authors.initials: N
authors.lastname: Hogg
authors.forename: Joy
authors.initials: J
authors.lastname: Joseph
authors.forename: B
authors.initials: B
authors.lastname: Kalyanaraman
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D005227:Fatty Acids / Q000378:metabolism; D005609:Free Radicals; D008051:Lipid Bilayers / Q000378:metabolism; D050356:Lipid Metabolism; D008081:Liposomes / Q000378:metabolism; D008567:Membranes, Artificial; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D009589:Nitrogen Oxides; D010100:Oxygen / Q000378:metabolism; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry*; D030421:Peroxynitrous Acid / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013096:Spermine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D005609:Free Radicals; D008051:Lipid Bilayers; D008081:Liposomes; D008567:Membranes, Artificial; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; D010455:Peptides; C091861:spermine nitric oxide complex; D030421:Peroxynitrous Acid; D013096:Spermine; D014443:Tyrosine; D009584:Nitrogen; D010100:Oxygen