title: Impacts of the charged residues mutation S48E/N62H on the thermostability and unfolding behavior of cold shock protein: insights from molecular dynamics simulation with Gō model.
abstract: The cold shock protein from the hyperthermophile Thermotoga maritima (Tm-Csp) exhibits significantly higher thermostability than its homologue from the thermophile Bacillus caldolyticus (Bc-Csp). Experimental studies have shown that the electrostatic interactions unique to Tm-Csp are responsible for improving its thermostability. In the present work, the favorable charged residues in Tm-Csp were grafted into Bc-Csp by a double point mutation of S48E/N62H, and the impacts of the mutation on the thermostability and unfolding/folding behavior of Bc-Csp were then investigated by using a modified Gō model, in which the electrostatic interactions between charged residues were considered in the model. Our simulation results show that this Tm-Csp-like charged residue mutation can effectively improve the thermostability of Bc-Csp without changing its two-state folding mechanism. Besides that, we also studied the unfolding kinetics and unfolding/folding pathway of the wild-type Bc-Csp and its mutant. It is found that this charged residue mutation obviously enhanced the stability of the C-terminal region of Bc-Csp, which decreases the unfolding rate and changes the unfolding/folding pathway of the protein. Our studies indicate that the thermostability, unfolding kinetics and unfolding/folding pathway of Bc-Csp can be artificially changed by introducing Tm-Csp-like favorable electrostatic interactions into Bc-Csp.
authors.affiliation: College of Science, Yanshan University, Qinhuangdao, 066004, China. jiguosu@ysu.edu.cn.
authors.forename: Ji-Guo
authors.initials: JG
authors.lastname: Su
authors.affiliation: College of Science, Yanshan University, Qinhuangdao, 066004, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Han
authors.affiliation: College of Science, Yanshan University, Qinhuangdao, 066004, China.
authors.forename: Shu-Xin
authors.initials: SX
authors.lastname: Zhao
authors.affiliation: College of Science, Yanshan University, Qinhuangdao, 066004, China.
authors.forename: Yan-Xue
authors.initials: YX
authors.lastname: Hou
authors.affiliation: College of Science, Yanshan University, Qinhuangdao, 066004, China.
authors.forename: Xing-Yuan
authors.initials: XY
authors.lastname: Li
authors.affiliation: Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics, Institute of Biophysics, Dezhou University, Dezhou, 253023, China.
authors.forename: Li-Sheng
authors.initials: LS
authors.lastname: Qi
authors.affiliation: Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics, Institute of Biophysics, Dezhou University, Dezhou, 253023, China. jhw25336@126.com.
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001407:Bacillus / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D009154:Mutation; D000072417:Protein Domains; D055550:Protein Stability; D017433:Protein Structure, Secondary; D058767:Protein Unfolding; D013045:Species Specificity; D055672:Static Electricity; D020124:Thermotoga maritima / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins
keywords: Coarse-grained model; Electrostatic interactions; Folding/unfolding; Langevin dynamics simulation; Thermophilic protein