Direct electrochemical oxidation of Abelson tyrosine-protein kinase 1 and evaluation of its interaction with synthetic substrate, ATP and inhibitors

• Electrochemical behaviour of Abelson tyrosine-protein kinase 1 (ABL1).
• In the native conformation one oxidation peak due to histidine residues.
• ABL1 conformational modifications detected through variation of oxidation peaks.
• Synthetic substrate abltide coils around the enzyme.
• ATP, imatinib and danusertib bind in stable complexes that maintain enzyme symmetry.

The electrochemical behaviour of Abelson protein-tyrosine kinase 1 (ABL1) and its interaction with synthetic substrate abltide EAIYAAPFAKKK, ATP, and inhibitors genistein, imatinib mesylate and danusertib were studied by differential pulse voltammetry using a glassy carbon electrode. In neutral electrolytes one oxidation peak due to histidine residues was observed. In acid and basic media the enzyme undergoes conformational modifications which lead to exposure of more electroactive amino acid to the electrode surface facilitating their oxidation. The interaction of ABL1 with the synthetic substrate involves the coiling of abltide around the enzyme which suppresses the oxidation of abltide tyrosine residue and leads the exposure of ABL1 electroactive amino acids to the electrode surface and occurrence of new electrochemical signals. The binding of ATP and ATP-competitive synthetic inhibitors imatinib mesylate, and danusertib results in stable complexes that maintains the symmetry of the enzyme but the electroactive centres of the compounds are hidden inside the binding site, preventing their oxidation. The natural inhibitor genistein is encountered on the outer surface of the enzyme and the electroactive centres are available for oxidation.

The electrochemical investigation of ABL1 electron-transfer reactions before and after interaction with substrates and inhibitors allows detection of proteins conformational modifications through the variation of electroactive amino-acids oxidation peaks.Figure optionsDownload as PowerPoint slide