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 I. Allakhverdiev

Research output: Contribution to journalArticlepeer-review

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 - 2018
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Materials Chemistry

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