title: Influence of C-terminal tail deletion on structure and stability of hyperthermophile Sulfolobus tokodaii RNase HI.
abstract: The C-terminus tail (G144-T149) of the hyperthermophile Sulfolobus tokodaii (Sto-RNase HI) plays an important role in this protein's hyperstabilization and may therefore be a good protein stability tag. Detailed understanding of the structural and dynamic effects of C-terminus tail deletion is required for gaining insights into the thermal stability mechanism of Sto-RNase HI. Focused on Sulfolobus tokodaii RNase HI (Sto-RNase HI) and its derivative lacking the C-terminal tail (ΔC6 Sto-RNase HI) (PDB codes: 2EHG and 3ALY), we applied molecular dynamics (MD) simulations at four different temperatures (300, 375, 475, and 500 K) to examine the effect of the C-terminal tail on the hyperstabilization of Sto-RNase HI and to investigate the unfolding process of Sto-RNase HI and ΔC6 Sto-RNase HI. The simulations suggest that the C-terminal tail has significant impact in hyperstabilization of Sto-RNase HI and the unfolding of these two proteins evolves along dissimilar pathways. Essential dynamics analysis indicates that the essential subspaces of the two proteins at different temperatures are non-overlapping within the trajectories and they exhibit different directions of motion. Our work can give important information to understand the three-state folding mechanism of Sto-RNase HI and to offer alternative strategies to improve the protein stability.
authors.affiliation: State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Ji-Long
authors.initials: JL
authors.lastname: Zhang
authors.forename: Qing-Chuan
authors.initials: QC
authors.lastname: Zheng
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Chu
authors.forename: Qiao
authors.initials: Q
authors.lastname: Xue
authors.forename: Hong-Xing
authors.initials: HX
authors.lastname: Zhang
authors.forename: Chia-Chung
authors.initials: CC
authors.lastname: Sun
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D055550:Protein Stability; D017433:Protein Structure, Secondary; D058767:Protein Unfolding; D016914:Ribonuclease H / Q000737:chemistry* / Q000235:genetics; D017384:Sequence Deletion; D016944:Sulfolobus / Q000201:enzymology*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D019843:Archaeal Proteins; D016914:Ribonuclease H; C078856:ribonuclease HI