title: Investigation of the binding network of IGF-I on the cavity surface of IGFBP4.
abstract: Insulin-like growth factor-binding proteins (IGFBPs) control bioactivity and distribution of insulin-like growth factors (IGFs) through high-affinity complex of IGFBP and IGF. To get more insight into the binding interaction of IGF system, the site-directed mutagenesis and force-driving desorption methods were employed to study the interaction mechanism of IGFBP4 and IGF-I by molecular dynamics (MD) simulation. In IGF-I, residues Gly7 to Asp12 were found to be the hot spots and they mainly anchored on the N-domain of IGFBP4. The contact area, the shape and size of protein, the surroundings of the binding site, the hydrophobic and electrostatic interaction between the two proteins worked as a complex network to regulate the protein-protein interaction. It was also found that the unfolding of the helix was not inevitable in the mutant, and it could be regulated by careful selection of the substituted amino acid.
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475001, Henan, China, xin_chen@henu.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Shuyan
authors.initials: S
authors.lastname: Zhu
authors.forename: Danhui
authors.initials: D
authors.lastname: Duan
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D001665:Binding Sites; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000737:chemistry* / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D060066:Protein Interaction Maps; D017433:Protein Structure, Secondary
chemical_list: D018974:Insulin-Like Growth Factor Binding Protein 4; D007334:Insulin-Like Growth Factor I