Figure 1
Some of the characterized products of the oxidation of protein-Trp residues.1414 Haywood, J.; Mozziconacci, O.; Allegre, K. M.; Kerwin, B. A.; Schöneich, C.; Mol. Pharmaceutics
2013, 10, 1146.,1919 Medinas, D. B.; Gozzo, F. C.; Santos, L. F. A.; Iglesias, A. H.; Augusto, O.; Free Radical Biol. Med.
2010, 49, 1046.,2626 Plowman, J. E.; Deb-Choudhury, S.; Grosvenor, A. J.; Dyer, J. M.; Photochem. Photobiol. Sci.
2013, 12, 1960.
27 Simat, T. J.; Steinhart, H.; J. Agric. Food Chem.
1998, 46, 490.
28 Sala, A.; Nicolis, S.; Roncone, R.; Casella, L.; Monzani, E.; Eur. J. Biochem.
2004, 271, 2841.
29 Yamakura, F.; Ikeda, K.; Nitric Oxide
2006, 14, 152.
30 Ehrenshaft, M.; Deterding, L. J.; Mason, R. P.; Free Radical Biol. Med.
2015, 89, 220.
31 Pattison, D. I.; Rahmanto, A. S.; Davies, M. J.; Photochem. Photobiol. Sci.
2011, 11, 38.-3232 Ronsein, G. E.; de Oliveira, M. C. B.; de Medeiros, M. H. G.; Di Mascio, P.; J. Am. Soc. Mass Spectrom.
2009, 20, 188.
Figure 3
Time-dependent dimerization of lysozyme upon UV irradiation (a) and MS/MS characterization of the produced dimer (b) and (c). (a) Representative SDS-PAGE analysis of the time-dependent lysozyme dimerization and aggregation in samples of lysozyme (0.14 mM) irradiated with UV light (254 nm; radiance of 6.3 mW cm-2) for the specified times in phosphate buffer (20 mM) containing DTPA (0.1 mM), pH 7.0. Aliquots corresponding to 30 µg protein were removed and analyzed by SDS-PAGE. The gel was stained with Coomassie Blue; (b) nano-ESI-Q-TOF-MS and (c) MS/MS analysis of the dimeric tryptic peptide (22GYSLGNWVCAAK33)2 obtained from lysozyme treated with UV light for 10 min. The MS/MS sequencing of the peak at m/z 883.41, which corresponds to the peptide (22GYSLGNWVCAAK33)2 (monoisotopic mass 2647.24 Da) with 3 charges is shown in (c) and its MS is shown in (b). The lysozyme dimer was isolated from the enzyme irradiated for 10 min as shown in (a); the samples were applied in 8 gel lanes, and the spots (at approximately 28 kDa) were excised from the gel, digested with trypsin, and subjected to ESI-Q-TOF-MS/MS analysis. Reprinted from reference 21 with permission.
Figure 4
Characterization of ditryptophan crosslinks produced by treatmente of Trp with the CO3•-. Trp (1 mM), DTPA (0.1 mM) and the carbonatotetramminecobalt(III) complex (4 mM) in phosphate buffer (20 mM), pH 7.0 were irradiated for 1 min with UV light at a wavelength of 254 nm (radiance of 6.3 mW cm-2) (abbreviated as Co/UVC).2121 Paviani, V.; Queiroz, R. F.; Marques, E. F.; Di Mascio, P.; Augusto, O.; Free Radical Biol. Med.
2015, 89, 72. The control corresponds to the same solution without irradiation. (a) Extraction ion chromatogram corresponding to ditryptophan (m/z 407.17 with one charge); (b) HPLC-ESI-Q-TOF-MS/MS analysis of the ion with m/z 407.17 corresponding to peaks 1, 2 and 3 shown in (a) as specified.