ABSTRACT
The studies on binding ability of longer chiral peptide nucleic acids (having four, six and eight thymines in a peptide side chain) have shown that the interactions between the nucleic base rings within a ligand molecule have a critical impact on the complex stability. Thymines inserted in the peptide side chain interact with each other as well as with peptide back-bone increasing the structural organization of the cPNA molecule. The metal ion coordination to cPNA, on the other hand, induces a very specific ligand structure, which may have a basic impact on the cPNA self-recognition processes.
Subject(s)
Copper/pharmacology , Nickel/pharmacology , Peptide Nucleic Acids/chemistry , Thymine/metabolism , Copper/metabolism , Drug Stability , Models, Molecular , Molecular Structure , Nickel/metabolism , Peptide Nucleic Acids/metabolism , Protein Structure, Secondary/drug effects , StereoisomerismABSTRACT
D,L-Dithiothreitol (DTT), known also as Cleland reagent, is a thiol group protectant, used commonly in peptide and protein chemistry. Therefore, it is often added at high concentrations in preparations of proteins relevant to heavy metal biochemistry. The coordination of five of these metal ions, Zn(II), Cd(II), Pb(II), Ni(II) and Cu(I) to DTT was studied by means of potentiometric titrations, and UV-Vis and NMR spectroscopies. It was found that DTT forms specific and very stable polymeric and monomeric complexes with all of these metal ions, using both of its sulfur donors. The quantitative description of these complexes in solution and the solid state provides the basis for predictions of interference from DTT in studies of metal ion binding of thiol-containing biomolecules.
