TY - JOUR
T1 - Tuning the redox potential of tyrosine-histidine bioinspired assemblies
AU - Odella, Emmanuel
AU - Moore, Thomas A.
AU - Moore, Ana L.
N1 - Funding Information:
The research leading to these results received funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Grant DE-FG02-03ER15393.
Funding Information:
The research leading to these results received funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Grant DE-FG02-03ER15393.
Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.
PY - 2022/2
Y1 - 2022/2
N2 - Photosynthesis powers our planet and is a source of inspiration for developing artificial constructs mimicking many aspects of the natural energy transducing process. In the complex machinery of photosystem II (PSII), the redox activity of the tyrosine Z (Tyrz) hydrogen-bonded to histidine 190 (His190) is essential for its functions. For example, the Tyrz–His190 pair provides a proton-coupled electron transfer (PCET) pathway that effectively competes against the back-electron transfer reaction and tunes the redox potential of the phenoxyl radical/phenol redox couple ensuring a high net quantum yield of photoinduced charge separation in PSII. Herein, artificial assemblies mimicking both the structural and redox properties of the Tyrz–His190 pair are described. The bioinspired constructs contain a phenol (Tyrz model) covalently linked to a benzimidazole (His190 model) featuring an intramolecular hydrogen bond which closely emulates the one observed in the natural counterpart. Incorporation of electron-withdrawing groups in the benzimidazole moiety systematically changes the intramolecular hydrogen bond strength and modifies the potential of the phenoxyl radical/phenol redox couple over a range of ~ 250 mV. Infrared spectroelectrochemistry (IRSEC) demonstrates the associated one-electron, one-proton transfer (E1PT) process upon electrochemical oxidation of the phenol. The present contribution provides insight regarding the factors controlling the redox potential of the phenol and highlights strategies for the design of futures constructs capable of transporting protons across longer distances while maintaining a high potential of the phenoxyl radical/phenol redox couple.
AB - Photosynthesis powers our planet and is a source of inspiration for developing artificial constructs mimicking many aspects of the natural energy transducing process. In the complex machinery of photosystem II (PSII), the redox activity of the tyrosine Z (Tyrz) hydrogen-bonded to histidine 190 (His190) is essential for its functions. For example, the Tyrz–His190 pair provides a proton-coupled electron transfer (PCET) pathway that effectively competes against the back-electron transfer reaction and tunes the redox potential of the phenoxyl radical/phenol redox couple ensuring a high net quantum yield of photoinduced charge separation in PSII. Herein, artificial assemblies mimicking both the structural and redox properties of the Tyrz–His190 pair are described. The bioinspired constructs contain a phenol (Tyrz model) covalently linked to a benzimidazole (His190 model) featuring an intramolecular hydrogen bond which closely emulates the one observed in the natural counterpart. Incorporation of electron-withdrawing groups in the benzimidazole moiety systematically changes the intramolecular hydrogen bond strength and modifies the potential of the phenoxyl radical/phenol redox couple over a range of ~ 250 mV. Infrared spectroelectrochemistry (IRSEC) demonstrates the associated one-electron, one-proton transfer (E1PT) process upon electrochemical oxidation of the phenol. The present contribution provides insight regarding the factors controlling the redox potential of the phenol and highlights strategies for the design of futures constructs capable of transporting protons across longer distances while maintaining a high potential of the phenoxyl radical/phenol redox couple.
KW - Bioinspired benzimidazole-phenols
KW - Infrared spectroelectrochemistry
KW - Proton-coupled electron transfer
KW - Tyrosine Z–His190 pair
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U2 - 10.1007/s11120-020-00815-x
DO - 10.1007/s11120-020-00815-x
M3 - Article
C2 - 33432530
AN - SCOPUS:85099094106
SN - 0166-8595
VL - 151
SP - 185
EP - 193
JO - Photosynthesis research
JF - Photosynthesis research
IS - 2
ER -