Thermodynamic and Structural Characterization of the Copper(II) Complexes of Peptides Containing Both Histidyl and Aspartyl Residues
Terminally protected pentapeptides with 2 histidines (Ac-HHVGD-NH2 and Ac-HVGDH-NH2) and the terminally free peptides containing both internal aspartyl and C-terminal histidyl residues (FDAH and VIDAH) have been synthesized, and copper(II) complexes studied by potentiometric, UV-Vis, CD, and EPR...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Hindawi Limited
2007-01-01
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| Series: | Bioinorganic Chemistry and Applications |
| Online Access: | http://dx.doi.org/10.1155/2007/30394 |
| Summary: | Terminally protected pentapeptides with 2 histidines (Ac-HHVGD-NH2 and Ac-HVGDH-NH2) and the terminally free peptides containing both internal aspartyl and C-terminal
histidyl residues (FDAH and VIDAH) have been synthesized, and copper(II) complexes studied by
potentiometric, UV-Vis, CD, and EPR spectroscopic techniques in solution. Both thermodynamic and
spectroscopic data reveal that side chain donor atoms of aspartyl and histidyl residues have a significant
contribution to the metal binding affinity of peptide molecules. In the case of terminally protected peptides, the
role of the imidazole-N donor functions is reflected in the enhanced stability of the 3N and 4N coordinated
copper(II) complexes. The amino and β-carboxylate groups of FDAH and VIDAH create a very effective metal binding site
with the (NH2, N−, β-COO−) and (NH2, N−, N−, β-COO−) coordination modes including the N-termini, while the histidine sites are available
for the formation of the (Nim, N−, N−) binding mode resulting in the preference of dinuclear complex formation. |
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| ISSN: | 1565-3633 1687-479X |