title: Conjugation of cytochrome c with ferrocene-terminated hyperbranched polymer and its influence on protein structure, conformation and function.
abstract: Interaction mechanism of a new hyperbranched polyurethane-based ferrocene (HPU-Fc) with cytochrome c (cyt c) and cyt c structure and conformation change induced by HPU-Fc were investigated using cyclic voltammogram(CV), differential pulse voltammetry (DPV), circular dichroism (CD), fluorescence, synchronous fluorescence and absorbance spectroscopy technique. The peroxidase activity of cyt c in the presence of HPU-Fc was also studied. The structure and conformation of protein are relatively stable at moderate concentration of HPU-Fc without obvious perturbation of the heme pocket and significant changes in protein secondary structure. Conjugation of cyt c with excessive HPU-Fc (over about 3 times of cyt c) slightly changed the α-helix structure in protein, disturbed the microenvironment around heme as well as away from the heme crevice, which caused the changes of the electrochemical behavior and the absorption spectra. Reasonable amount of HPU-Fc has no significant influence on the protein enzymatic activity, while excess HPU-Fc may cause a conformation not suitable for H2O2 activation and guaiacol oxidation. The interaction of HPU-Fc with cyt c and the conservation of protein function at suitable HPU-Fc amount make prepared complex promising for the synergistic anticancer therapy.
authors.affiliation: School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China. Electronic address: xfj66@126.com.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Xiao
authors.affiliation: School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China. Electronic address: yuelin@stdu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Yue
authors.affiliation: School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China. Electronic address: songli@stdu.edu.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.affiliation: School of Material Science and Engineering, Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, No. 17 North 2nd-Ring East Road, Shijiazhuang 050043, Hebei Province, China. Electronic address: lixinxin@stdu.edu.cn.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D045304:Cytochromes c / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D006139:Guaiacol / Q000737:chemistry*; D006736:Horses; D006861:Hydrogen Peroxide / Q000737:chemistry*; D000075163:Metallocenes; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D011140:Polyurethanes; D006139:Guaiacol; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D009195:Peroxidase; C004998:ferrocene
keywords: Circular dichroism; Conformational change; Cytochrome c; Electrochemical behavior; Ferrocene-terminated hyperbranched polymer; Fluorescence; Interaction mechanism