Title: Effect of the protein structure and heme iron coordination sphere on the long-range electron transfer from hematite and zinc oxide nanostructures to cytochrome c

Authors: Lucivaldo R. Menezes; Juliana C. Araújo-Chaves; David M. Lopes; Julia D. Bronzato; Guilherme Sombrio; Denise Criado; Alejandro Zúñiga; Alexandre J.C. Lanfredi; José A. Souza; Iseli L. Nantes-Cardoso

Addresses: Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Center of Engineering and Applied Social Sciences, Federal University of ABC, Santo André, SP, 09210-580, Brazil ' Center of Engineering and Applied Social Sciences, Federal University of ABC, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil ' Federal University of ABC, Center of Natural Sciences and Humanities, Santo André, SP, 09210-580, Brazil

Abstract: Cytochrome c has gained increasing interest in non-biological areas because of its electronic and magnetic properties that are applicable in spintronics and energy. The chiral helicoidal structure of cytochrome c gives to this protein the property of chiral-induced spin selectivity (CISS) applicable to spintronics and energy. In a previous study, it was demonstrated that Fe₂O₃, structured as layers of nanowires (NWs) and nanoflakes (NFs), contrary to ZnONWs, can efficiently reduce cytochrome c heme when submitted to illumination with a sunlight simulator. The present study investigated the influence of α-helix content and heme iron axial ligands on the capacity of cytochrome c to accept electrons from Fe₂O₃NWs (NFs) pristine and decorated with gold nanoparticles. Microperoxidase-11 (MP-11), a heme-undecapeptide produced by cytochrome c digestion was irradiated in the presence of Fe₂O₃NFs. Efficient photoreduction was observed only for MP-11 with hexacoordinated heme iron. The results demonstrated that the heme coordination sphere rather than the α-helix content is crucial for the efficient long-range electron transfer from hematite to heme iron. Also, ZnO grown as nanoflowers (NFws) at room temperature was tested as a photoreduction agent, and like ZnONWs was also an inefficient photoreduction agent for cytochrome c.

Keywords: long-range electron transfer; semiconductors; zinc oxide; hematite; cytochrome c; microperoxidase-11; heme iron coordination sphere; CISS effect; nanoflakes; nanowires.

DOI: 10.1504/IJNT.2020.109349

International Journal of Nanotechnology, 2020 Vol.17 No.1, pp.42 - 56

Published online: 03 Sep 2020 *

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