CuII and NiII Interactions with the Terminally Blocked Hexapeptide Ac-Leu-Ala-His-Tyr-Asn-Lys-amide Model of Histone H2B 80–85Reportar como inadecuado




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Bioinorganic Chemistry and ApplicationsVolume 2008 2008, Article ID 257038, 10 pages

Research Article

Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece

Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA

Received 22 December 2007; Accepted 4 February 2008

Academic Editor: Imre Sovago

Copyright © 2008 Katerina Panagiotou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The N- and C-terminal blocked hexapeptide Ac-Leu-Ala-His-Tyr-Asn-Lys-amide LAHYNK representing the 80–85 fragment of histone H2B was synthesized and its interactions with CuII and NiII ions were studied by potentiometric, UV-Vis, CD, EPR, and NMR spectroscopic techniques in solution. Our data reveal that the imidazole N3 nitrogen atom is the primary ligating group for both metal ions. Sequential amide groups deprotonation and subsequent coordination to metal ions indicated an coordination mode above , in all cases. In the case of CuII-peptide system, the almost exclusive formation of the predominant species CuL in neutral media accounting for almost 98% of the total metal ion concentration at pH 7.3 strongly indicates that at physiological pH values the sequence -LAHYNK- of histone H2B provides very efficient binding sites for metal ions. The imidazole pyrrole N1 ionization but not coordination was also detected in species CuH-4L present in solution above .





Autor: Katerina Panagiotou, Maria Panagopoulou, Tilemachos Karavelas, Vassiliki Dokorou, Andrew Hagarman, Jonathan Soffer, Reinhard

Fuente: https://www.hindawi.com/



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