title: Structure and flexibility of the thermophilic cold-shock protein of Thermus aquaticus.
abstract: The thermophilic bacterium Thermus aquaticus is a well-known source of Taq polymerase. Here, we studied the structure and dynamics of the T. aquaticus cold-shock protein (Ta-Csp) to better understand its thermostability using NMR spectroscopy. We found that Ta-Csp has a five-stranded β-barrel structure with five salt bridges which are important for more rigid structure and a higher melting temperature (76 °C) of Ta-Csp compared to mesophilic and psychrophilic Csps. Microsecond to millisecond time scale exchange processes occur only at the β1-β2 surface region of the nucleic acid binding site with an average conformational exchange rate constant of 674 s(-1). The results imply that thermophilic Ta-Csp has a more rigid structure and may not need high structural flexibility to accommodate nucleic acids upon cold shock compared to its mesophile and psychrophile counterparts.
authors.affiliation: Department of Bioscience and Biotechnology, BMIC, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Bonghwan
authors.initials: B
authors.lastname: Jin
authors.affiliation: Department of Bioscience and Biotechnology, BMIC, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Ki-Woong
authors.initials: KW
authors.lastname: Jeong
authors.affiliation: Department of Bioscience and Biotechnology, BMIC, Konkuk University, Seoul 143-701, South Korea. Electronic address: ymkim@konkuk.ac.kr.
authors.forename: Yangmee
authors.initials: Y
authors.lastname: Kim
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D002942:Circular Dichroism; D057773:Cold Shock Proteins and Peptides / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D055550:Protein Stability; D017433:Protein Structure, Secondary; D013824:Thermus / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D057773:Cold Shock Proteins and Peptides
keywords: Backbone dynamics; Cold-shock proteins; NMR spectroscopy; Structure; Thermus aquaticus