The binding of Cu(II) by the peptide with β-Asp located in non-coordinating site – Solution and structural studies

In the present study, the coordination abilities of Ac-TLEGTKKGHKLHLβDY-NH2 peptide (the analogue of SPARC 114–128 fragment containing β-Asp127 residue) are discussed. The analysis is provided based on the results of potentiometric and spectroscopic measurements supported by quantum-chemical calculations. Presented results clearly show that the β-Asp amino acid residue may influence the efficiency of metal ion binding despite the fact that it is not directly involved in metal ion binding. Moreover, in order to further characterize experimentally observed species, we performed quantum-chemical calculations for structures mimicking SPARC 114–128 fragment as a step towards a better understanding of structural and energetical aspects related to the coordination abilities of the analogue of SPARC fragment.