title: Probing the Folding-Unfolding Transition of a Thermophilic Protein, MTH1880.
abstract: The folding mechanism of typical proteins has been studied widely, while our understanding of the origin of the high stability of thermophilic proteins is still elusive. Of particular interest is how an atypical thermophilic protein with a novel fold maintains its structure and stability under extreme conditions. Folding-unfolding transitions of MTH1880, a thermophilic protein from Methanobacterium thermoautotrophicum, induced by heat, urea, and GdnHCl, were investigated using spectroscopic techniques including circular dichorism, fluorescence, NMR combined with molecular dynamics (MD) simulations. Our results suggest that MTH1880 undergoes a two-state N to D transition and it is extremely stable against temperature and denaturants. The reversibility of refolding was confirmed by spectroscopic methods and size exclusion chromatography. We found that the hyper-stability of the thermophilic MTH1880 protein originates from an extensive network of both electrostatic and hydrophobic interactions coordinated by the central β-sheet. Spectroscopic measurements, in combination with computational simulations, have helped to clarify the thermodynamic and structural basis for hyper-stability of the novel thermophilic protein MTH1880.
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-740, Korea.
authors.forename: Heeyoun
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Physics, Pusan National University, Busan, 609-735, Korea.|Center for Proteome Biophysics, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 711-873, Korea.
authors.forename: Sangyeol
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-740, Korea.
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Jung
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-740, Korea.
authors.forename: Jeongmin
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-740, Korea.
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Yun
authors.affiliation: Center for Proteome Biophysics, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 711-873, Korea.|Department of Brain and Cognitive Sciences, DGIST, Daegu, 711-873, Korea.
authors.forename: Iksoo
authors.initials: I
authors.lastname: Chang
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-740, Korea.
authors.forename: Weontae
authors.initials: W
authors.lastname: Lee
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D013696:Temperature; D013816:Thermodynamics; D014508:Urea / Q000494:pharmacology
chemical_list: D019843:Archaeal Proteins; D014508:Urea