title: Structure and catalytic behavior of myoglobin adsorbed onto nanosized hydrotalcites.
abstract: The adsorption of myoglobin (Mb) onto nanosized nickel aluminum hydrotalcite (NiAl-HTlc) surface was studied, and the structural properties of the resulting protein layer were analyzed by using FT-IR, Raman, and fluorescence spectroscopies. Upon adsorption onto the nanoparticle surface, the protein molecules maintained their secondary structure, while the tertiary structure was altered. The fluorescence spectra and anisotropy values of adsorbed Mb revealed that the emitting amino acid residues are affected by different microenvironments when compared to the native protein behavior. Moreover, the decrease of fluorescence decay times of tryptophan indicated the occurrence of interactions among the fluorophores and the constituents of the nanoparticles, such as the metal cations, which can take place when conformational changes of Mb occur. Raman spectra indicated that the interaction of Mb molecules with NiAl-HTlc nanoparticles modified the porphyrin core, changing the spin state of the heme iron from high spin (HS) to low spin (LS). The enzymatic activity of the nanostructured biocomposite was evaluated in the oxidation of 2-methoxyphenol by hydrogen peroxide and discussed on the basis of structural properties of adsorbed myoglobin.
authors.affiliation: Dipartimento di Chimica, Università di Perugia, via Elce di Sotto, 8, 06123 Perugia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bellezza
authors.forename: Antonio
authors.initials: A
authors.lastname: Cipiciani
authors.forename: Loredana
authors.initials: L
authors.lastname: Latterini
authors.forename: Tamara
authors.initials: T
authors.lastname: Posati
authors.forename: Paola
authors.initials: P
authors.lastname: Sassi
mesh_terms: D000327:Adsorption; D000535:Aluminum / Q000737:chemistry; D000536:Aluminum Hydroxide / Q000737:chemistry*; D000818:Animals; D055162:Biocatalysis; D006139:Guaiacol / Q000737:chemistry; D006418:Heme / Q000737:chemistry; D006736:Horses; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000378:metabolism; D011166:Porphyrins / Q000737:chemistry; D011487:Protein Conformation; D013057:Spectrum Analysis; D014364:Tryptophan / Q000737:chemistry
chemical_list: D055767:Immobilized Proteins; D009211:Myoglobin; D011166:Porphyrins; C010467:hydrotalcite; D006418:Heme; D000536:Aluminum Hydroxide; D006139:Guaiacol; D009532:Nickel; D014364:Tryptophan; D006861:Hydrogen Peroxide; D000535:Aluminum; D007501:Iron; D009195:Peroxidase; D008276:Magnesium Hydroxide