Dresden 2020 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Poster Session - Solid-liquid Interfaces: Structure, Spectroscopy
O 29.3: Poster
Montag, 16. März 2020, 18:15–20:00, P1A
Determining redox-dependent Cu-ligand chelating behaviour in a single metallo-protein — •Giovanni Giuzio1, Masoud Baghernejad1,2, and Katrin F. Domke1 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Hemholtz-Institute, Münster, Germany
The copper metallo-protein azurin is a widely studied system in which ET is performed under physiological conditions by switching the oxidation state of the Cu center between +1 and +2.
In the presented project, we study individual azurin proteins bound to a Au(111) surface combining scanning tunneling microscopy and TERS under electrochemical conditions. In-air TER spectra show that the electronic, optical and vibrational properties of the azurin Cu center are preserved upon molecule conjugation with the Au surface. STM images prove that we TERS-probe individual proteins at a time.
Under EC conditions, we control the Au(111) potential which in turn regulates the oxidation state of the Cu center. The results show a potential-dependent behavior of the TER spectra. Comparing the S/N of in-air and in-liquid EC-experiment, a drastic signal reduction is observed under operando conditions. To improve the EC-TERS sensitivity, we use a spatial light modulator to optimize the laser-tip coupling, using either the focus size or the TER signal as a feedback. TERS potentio-dynamic mapping of a single molecule switch and extracting structural information about the metallo-protein under switching conditions can be expected to provide unprecedented insights into ET transfer characteristics in biomolecular switches.