Thermostability of the N-terminal RNA-binding domain of the SARS-CoV nucleocapsid protein: experiments and numerical simulations.
Differential scanning calorimetry, circular dichroism spectroscopy, nuclear magnetic resonance spectroscopy, and numerical simulations were used to study the thermostability of the N-terminal RNA-binding domain (RBD) of the SARS-CoV nucleocapsid protein. The transition temperature of the RBD in a mixing buffer, composed of glycine, sodium acetate, and sodium phosphate with 100 mM sodium chloride, at pH 6.8, determined by differential scanning calorimetry and circular dichroism, is 48.74 degrees C. Experimental results showed that the thermal-induced unfolding-folding transition of the RBD follows a two-state model with a reversibility >90%. Using a simple Gō-like model and Langevin dynamics we have shown that, in agreement with our experiments, the folding of the RBD is two-state. Theoretical estimates of thermodynamic quantities are in reasonable agreement with the experiments. Folding and thermal unfolding pathways of the RBD also were experimentally and numerically studied in detail. It was shown that the strand beta(1) from the N-terminal folds last and unfolds first, while the remaining beta-strands fold/unfold cooperatively.
Fang
Huey-Jen
HJ
Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan.
Chen
Yong-Zhong
YZ
Li
Mai Suan
MS
Wu
Ming-Chya
MC
Chang
Chun-Ling
CL
Chang
Chung-ke
CK
Hsu
Yen-lan
YL
Huang
Tai-huang
TH
Chen
Hueih-Min
HM
Tsong
Tian-Yow
TY
Hu
Chin-Kun
CK
D000465:Algorithms; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D003198:Computer Simulation; D000086462:Coronavirus Nucleocapsid Proteins; D008956:Models, Chemical; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D044366:Transition Temperature
D000086462:Coronavirus Nucleocapsid Proteins; D019590:Nucleocapsid Proteins; D012313:RNA