Proceedings book download - 5Z.com

with Zn 2+ ions. Peptides containing βAsp in position 1 or 2 ([ Asp 1 ]DHGH, [ Asp 1 ]AT,[ Asp 2 ]FPA) have a very low affinity towards Zn 2+ but the complexes that are formed aremuch more stabile than those with Cu 2+ . Surprisingly, [ Asp 14 ]AcSPARC-NH 2 peptide wasa poor ligand for Cu 2+ and Zn 2+ ions even though it contains two His residues.The analysis of CID ESI-MS/MS spectra of the peptide-metal ion complexes allowedus to draw some conclusions on the most probable sites of the metal ion binding. Forexample, in case of the Ubq 50-59 fragment analogues Cu 2+ ions interact mainly with theN-terminal amino group and the Glu 2 residue. For the model peptide [ Asp 1 ]DHGH and[ Asp 14 ]AcSPARC-NH 2 the major binding sites for Cu 2+ are both His residues.Presented results are in a very good agreement with those obtained by more traditionalmethods applied to study peptide–metal interactions (potentiometry, UV-Vis). This provesthat the mass spectrometry may provide reliable information not only on the stoichiometryof the peptide-metal complexes, but also on the binding mode and the localization of themetal ion within the complex.[M+2H] 2+[%]Intensity584.77[M+Cu] 2+615.22615.224615.726 616.223 616.726+MS, 0.0-0.3min #(3-22)[%]Intensity.[M+2H] 2+ [M+H] +584.7880615.235617.226C49H77N13O20Cu, M ,1230.4780615.736 616.234 616.735[M+Na+H] 2+60595.3617.237 617.739614.5 615.0 615.5 616.0 616.5 617.0 617.5 618.0 m/z604040455.24[M+Cu-H] +[M+H] + 1229.431168.522020511.201037.43[M+Na+H] 2+1037.441168.53696.32455.25494.24[M+Cu] 2+615.250400 500 600 700 800 900 1000 1100 1200 m/z0400 500 600 700 800 900 1000 1100 1200 m/zFig. 1. ESI-MS spectra of Ubq 50-59 (left) and [ -Asp 3 ]Ubq 50-59 (right) in the presence ofCu 2+ . Inserts show isotopic patterns of the indicated peak; top spectra was measured, thebottom one was calculated.AcknowledgmentsThis work was supported in part by grant No. N N401 222734 from the Ministry of Science andHigher Education (Poland).References1. Earle, S.A., El-Haddad, A., et al. Transplantation 82, 1544-1546 (2006).2. Szewczuk, Z., Stefanowicz, P., et al. Biopolymers 74, 325-362 (2004).3. Jaremko, L., Jaremko, M., et al. Biopolymers 91, 423-4314 (2009).4. Liu, D., Seuthe, A.B., et al. J. Am. Chem. Soc. 127, 2024-2025 (2005).5. Brasun, J., Cebrat, M., et al. J. Inorg. Bioch. 103, 1033-1038 (2009).6. Brasun, J., Cebrat, M., et al. Dalton Trans. 853-4857 (2009).597