Links between peptides and Mn oxide: Nano-sized manganese oxide embedded in a peptide matrix

Mohammad Mahdi Najafpour, Sepideh Madadkhani, Somayyeh Akbarian, Zahra Zand, Małgorzata Hołyńska, Mohsen Kompany-Zareh, Tomo Tatsuya, Jitendra Pal Singh, Keun Hwa Chae, Suleyman Allakhverdiev

Research output: Contribution to journalArticle

1 Citation (Scopus)

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.

Original languageEnglish
Pages (from-to)10067-10077
Number of pages11
JournalNew Journal of Chemistry
Volume42
Issue number12
DOIs
Publication statusPublished - Jan 1 2018
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Materials Chemistry

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  • Cite this

    Najafpour, M. M., Madadkhani, S., Akbarian, S., Zand, Z., Hołyńska, M., Kompany-Zareh, M., Tatsuya, T., Singh, J. P., Chae, K. H., & Allakhverdiev, S. (2018). Links between peptides and Mn oxide: Nano-sized manganese oxide embedded in a peptide matrix. New Journal of Chemistry, 42(12), 10067-10077. https://doi.org/10.1039/c8nj02119h