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Issue 12, 2018
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Links between peptides and Mn oxide: nano-sized manganese oxide embedded in a peptide matrix

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Abstract

Herein we report on a poly-peptide/Mn oxide nanocomposite as a model for the water-oxidizing catalyst in Photosystem II. The material is obtained by the reaction of poly-L-tyrosine, Mn(OAc)2·4H2O and KMnO4. HRTEM images of the nanocomposite indicate the presence of nanoparticles dispersed in a poly-L-tyrosine matrix with no crystalline phases. A broad peak at ∼400–550 nm in the UV-visible spectrum is related to Mn oxide formation. X-ray absorption studies suggest that the Mn atoms are in the oxidation state of +IV and a coordination number of around three was obtained for Mn in the structure. The water-oxidizing activity of the material under electrochemical conditions was also investigated. Electrochemical experiments proved the presence of Mn(IV) oxide. Determination of oxygen coupled to electrochemistry revealed the role of poly-L-tyrosine in decreasing the overpotential for water oxidation. In the next step, the interaction of the nanocomposite and imidazole as a model for the tyrosine 161 and histidine 190 residues in Photosystem II was studied with fluorescence spectroscopy using the multivariate curve resolution-alternating least squares method.

Graphical abstract: Links between peptides and Mn oxide: nano-sized manganese oxide embedded in a peptide matrix

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Publication details

The article was received on 01 May 2018, accepted on 04 May 2018 and first published on 09 May 2018


Article type: Paper
DOI: 10.1039/C8NJ02119H
Citation: New J. Chem., 2018,42, 10067-10077
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    Links between peptides and Mn oxide: nano-sized manganese oxide embedded in a peptide matrix

    M. M. Najafpour, S. Madadkhani, S. Akbarian, Z. Zand, M. Hołyńska, M. Kompany-Zareh, T. Tatsuya, J. P. Singh, K. H. Chae and S. I. Allakhverdiev, New J. Chem., 2018, 42, 10067
    DOI: 10.1039/C8NJ02119H

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