Wydział Chemii

A. Matera

Justyna Brasuń

Marek Cebrat

Jolanta Świątek-Kozłowska

2008

Polyhedron

27

1539-1555

10.1016/j.poly.2007.12.035

Naukowa

Angielski

Artykuł

Cu²⁺ complexes with peptides containing three histidine residues have very specific metal binding abilities and can mimic the structures of various multi-histidine metal binding sites in proteins. The main goal of the work concerns the investigations of coordination abilities of the group of N-terminally protected Ac-His-Arg-His-Gly-His-Gly, Ac-His-Gly-His-Arg-His-Gly, Ac-Gly-His-His-Arg-His-Gly and Ac-His-His-Gly-His-Arg-Gly, and their unprotected analogs His-Arg-His-Gly-His-Gly, His-Gly-His-Arg-His-Gly, Gly-His-His-Arg-His-Gly and His-His-Gly-His-Arg-Gly towards Cu²⁺ ions. Detailed spectroscopic (UV/Vis, CD and EPR) and potentiometric studies have been made. The stoichiometry and binding mode for each ligand–Cu²⁺ system were determined.In the case of N-terminally protected peptides the coordination begins at the imidazole nitrogen(s) which act as the anchoring groups. At physiological pH the {3N_im, 2N⁻} binding pattern is suggested and at high pH three amide nitrogens are involved in Cu²⁺ binding.According to the coordination abilities of the unprotected peptides, the position of the histidine residue determines the coordination mode. For His¹ peptides the histamine-like {NH₂, N_im} mode for the first species is suggested. The final albumin-like coordination mode is proposed not only for HGHRHG and HRHGHG but also for GHHRHG. For ligands with the His-Xaa-His motif the {2N⁻, 2N_im} binding mode is formed easier. For ligands with His² the 3N complex with the {NH₂, N⁻, N_im} binding pattern is a dominant species within the physiological pH range.The protection of the amine group caused a significant decrease of the coordination abilities of the peptides.

Peptides, Histidine, Copper (II), Coordination chemistry

https://doi.org/10.1016/j.poly.2007.12.035

http://www.elsevier.com