“Out of Pocket” Protein Binding—A Dilemma of Epitope Imprinted Polymers Revealed for Human Hemoglobin
Xiaorong Zhang,
Giorgio Caserta,
Aysu Yarman,
Eszter Supala,
Armel F. Tadjoung Waffo,
Ulla Wollenberger,
Róbert E. Gyurcsányi,
Ingo Zebger,
Frieder W. Scheller
Affiliations
Xiaorong Zhang
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Str. 24–25, 14476 Potsdam, Germany
Giorgio Caserta
Institut für Chemie, PC 14 Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
Aysu Yarman
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Str. 24–25, 14476 Potsdam, Germany
Eszter Supala
BME “Lendület” Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, 1111 Budapest, Hungary
Armel F. Tadjoung Waffo
Institut für Chemie, PC 14 Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
Ulla Wollenberger
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Str. 24–25, 14476 Potsdam, Germany
Róbert E. Gyurcsányi
BME “Lendület” Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, 1111 Budapest, Hungary
Ingo Zebger
Institut für Chemie, PC 14 Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
Frieder W. Scheller
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Str. 24–25, 14476 Potsdam, Germany
The epitope imprinting approach applies exposed peptides as templates to synthesize Molecularly Imprinted Polymers (MIPs) for the recognition of the parent protein. While generally the template protein binding to such MIPs is considered to occur via the epitope-shaped cavities, unspecific interactions of the analyte with non-imprinted polymer as well as the detection method used may add to the complexity and interpretation of the target rebinding. To get new insights on the effects governing the rebinding of analytes, we electrosynthesized two epitope-imprinted polymers using the N-terminal pentapeptide VHLTP-amide of human hemoglobin (HbA) as the template. MIPs were prepared either by single-step electrosynthesis of scopoletin/pentapeptide mixtures or electropolymerization was performed after chemisorption of the cysteine extended VHLTP peptide. Rebinding of the target peptide and the parent HbA protein to the MIP nanofilms was quantified by square wave voltammetry using a redox probe gating, surface enhanced infrared absorption spectroscopy, and atomic force microscopy. While binding of the pentapeptide shows large influence of the amino acid sequence, all three methods revealed strong non-specific binding of HbA to both polyscopoletin-based MIPs with even higher affinities than the target peptides.
