title: An engineered polypeptide around nano-sized manganese-calcium oxide: copying plants for water oxidation.
abstract: Synthesis of new efficient catalysts inspired by Nature is a key goal in the production of clean fuel. Different compounds based on manganese oxide have been investigated in order to find their water-oxidation activity. Herein, we introduce a novel engineered polypeptide containing tyrosine around nano-sized manganese-calcium oxide, which was shown to be a highly active catalyst toward water oxidation at low overpotential (240 mV), with high turnover frequency of 1.5 × 10(-2) s(-1) at pH = 6.3 in the Mn(III)/Mn(IV) oxidation range. The compound is a novel structural and efficient functional model for the water-oxidizing complex in Photosystem II. A new proposed clever strategy used by Nature in water oxidation is also discussed. The new model of the water-oxidizing complex opens a new perspective for synthesis of efficient water-oxidation catalysts.
authors.affiliation: Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran. mmnajafpour@iasbs.ac.ir.
authors.forename: Mohammad Mahdi
authors.initials: MM
authors.lastname: Najafpour
authors.forename: Mohadeseh Zarei
authors.initials: MZ
authors.lastname: Ghobadi
authors.forename: Bahram
authors.initials: B
authors.lastname: Sarvi
authors.forename: Behzad
authors.initials: B
authors.lastname: Haghighi
mesh_terms: D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002384:Catalysis; D020134:Catalytic Domain; D004563:Electrochemistry; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D015202:Protein Engineering / Q000379:methods*; D013055:Spectrophotometry, Infrared; D014443:Tyrosine / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D017895:Manganese Compounds; D010087:Oxides; D010455:Peptides; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D014867:Water; D014443:Tyrosine; D008345:Manganese; C027424:manganese oxide; C016538:lime; D010100:Oxygen; D002118:Calcium