title: Mimicking hemoproteins: a new synthetic metalloenzyme based on a Fe(III)-mesoporphyrin functionalized by two helical decapeptides.
abstract: A new metalloenzyme formed by a Fe(III)-mesoporphyrin IX functionalized by two helical decapeptides was synthesized to mimic function and structural features of a hemoprotein active site. Each decapeptide comprises six 2-aminoisobutyric acid residues, which constrain the peptide to attain a helical conformation, and three glutamic residues for improving the solubility of the catalyst in aqueous solutions. The new compound shows a marked amphiphilic character, featuring a polar outer surface and a hydrophobic inner cavity that hosts the reactants in a restrained environment where catalysis may occur. The catalytic activity of this synthetic mini-protein was tested with respect to the oxidation of L- and D-Dopa by hydrogen peroxide, showing moderate stereoselectivity. Structural information on the new catalyst and its adduct with the L- or D-Dopa substrate were obtained by the combined use of spectroscopic techniques and molecular mechanics calculations.
authors.affiliation: Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Mariano
authors.initials: M
authors.lastname: Venanzi
authors.forename: Sabrina
authors.initials: S
authors.lastname: Cianfanelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Palleschi
mesh_terms: D020134:Catalytic Domain; D004295:Dihydroxyphenylalanine / Q000737:chemistry; D006420:Hemeproteins / Q000138:chemical synthesis*; D007700:Kinetics; D008652:Mesoporphyrins / Q000737:chemistry*; D008667:Metalloproteins / Q000138:chemical synthesis*; D008958:Models, Molecular; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000737:chemistry; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000138:chemical synthesis*; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D006420:Hemeproteins; D008652:Mesoporphyrins; D008667:Metalloproteins; D009842:Oligopeptides; C031468:mesoporphyrin IX; D004295:Dihydroxyphenylalanine; D010544:Peroxidases
keywords: Aib; Dopa oxidation kinetics; helical oligopeptides; hemoprotein models; mini-enzyme; peptide catalyst