title: Caseoperoxidase, mixed β-casein-SDS-hemin-imidazole complex: a nano artificial enzyme.
abstract: A novel peroxidase-like artificial enzyme, named "caseoperoxidase", was biomimetically designed using a nano artificial amino acid apo-protein hydrophobic pocket. This four-component nano artificial enzyme containing heme-imidazole-β-casein-SDS exhibited high activity growth and k(cat) performance toward the native horseradish peroxidase demonstrated by the steady state kinetics using UV-vis spectrophotometry. The hydrophobicity and secondary structure of the caseoperoxidase were studied by ANS fluorescence and circular dichroism spectroscopy. Camel β-casein (Cβ-casein) was selected as an appropriate apo-protein for the heme active site because of its innate flexibility and exalted hydrophobicity. This selection was confirmed by homology modeling method. Heme docking into the newly obtained Cβ-casein structure indicated one heme was mainly incorporated with Cβ-casein. The presence of a main electrostatic site for the active site in the Cβ-casein was also confirmed by experimental methods through Wyman binding potential and isothermal titration calorimetry. The existence of Cβ-casein protein in this biocatalyst lowered the suicide inactivation and provided a suitable protective role for the heme active-site. Additional experiments confirmed the retention of caseoperoxidase structure and function as an artificial enzyme.
authors.affiliation: a Chemistry & Chemical Engineering Research Center of Iran (CCERCI) , Tehran , Iran.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Moosavi-Movahedi
authors.affiliation: b Faculty of Science, Department of Chemistry , Tarbiat Modares University , Tehran , Iran.
authors.forename: Hussein
authors.initials: H
authors.lastname: Gharibi
authors.affiliation: c Department of Biological Sciences , Institute for Advanced Studies in Basic Sciences (IASBS) , Zanjan , Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Hadi-Alijanvand
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Akbarzadeh
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.
authors.forename: Mansoore
authors.initials: M
authors.lastname: Esmaili
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.
authors.forename: Maliheh S
authors.initials: MS
authors.lastname: Atri
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Sefidbakht
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.
authors.forename: Mousa
authors.initials: M
authors.lastname: Bohlooli
authors.affiliation: e Research Institute of Petroleum Industry , Tehran , Iran.
authors.forename: Khodadad
authors.initials: K
authors.lastname: Nazari
authors.affiliation: b Faculty of Science, Department of Chemistry , Tarbiat Modares University , Tehran , Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Javadian
authors.affiliation: f College of Life Science , Henan University , Kaifeng 475000 , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Hong
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.|g Center of Excellence in Biothermodynamics, University of Tehran , Tehran , Iran.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Saboury
authors.affiliation: h Department of Ophthalmology and Visual Sciences , Biomedical Engineering, University of Wisconsin School of Medicine and Public Health , Madison , WI , USA.|i McPherson Eye Research Institute, University of Wisconsin School of Medicine and Public Health , Madison , WI , USA.
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
authors.affiliation: d Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran.|g Center of Excellence in Biothermodynamics, University of Tehran , Tehran , Iran.|i McPherson Eye Research Institute, University of Wisconsin School of Medicine and Public Health , Madison , WI , USA.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Moosavi-Movahedi
mesh_terms: D001665:Binding Sites; D055162:Biocatalysis; D032701:Biomimetics / Q000379:methods; D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D002942:Circular Dichroism; D006427:Hemin / Q000737:chemistry* / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D007093:Imidazoles / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry* / Q000378:metabolism; D013053:Spectrophotometry
chemical_list: D002364:Caseins; D007093:Imidazoles; D046912:Multiprotein Complexes; D012967:Sodium Dodecyl Sulfate; D006427:Hemin; C029899:imidazole; D006735:Horseradish Peroxidase
keywords: SDS monomer; artificial enzyme; biomimetic; camel β-casein; caseoperoxidase; heme; horseradish peroxidase (HRP); imidazole