title: Reversible thermal unfolding of a yfdX protein with chaperone-like activity.
abstract: yfdX proteins are ubiquitously present in a large number of virulent bacteria. A member of this family of protein in E. coli is known to be up-regulated by the multidrug response regulator. Their abundance in such bacteria suggests some important yet unidentified functional role of this protein. Here, we study the thermal response and stability of yfdX protein STY3178 from Salmonella Typhi using circular dichroism, steady state fluorescence, dynamic light scattering and nuclear magnetic resonance experiments. We observe the protein to be stable up to a temperature of 45 °C. It folds back to the native conformation from unfolded state at temperature as high as 80 °C. The kinetic measurements of unfolding and refolding show Arrhenius behavior where the refolding involves less activation energy barrier than that of unfolding. We propose a homology model to understand the stability of the protein. Our molecular dynamic simulation studies on this model structure at high temperature show that the structure of this protein is quite stable. Finally, we report a possible functional role of this protein as a chaperone, capable of preventing DTT induced aggregation of insulin. Our studies will have broader implication in understanding the role of yfdX proteins in bacterial function and virulence.
authors.affiliation: Department of Chemical, Biological And Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt lake, Kolkata 700106, India.
authors.forename: Paramita
authors.initials: P
authors.lastname: Saha
authors.affiliation: Department of Chemical, Biological And Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt lake, Kolkata 700106, India.
authors.forename: Camelia
authors.initials: C
authors.lastname: Manna
authors.affiliation: Department of Chemical, Biological And Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt lake, Kolkata 700106, India.
authors.forename: Jaydeb
authors.initials: J
authors.lastname: Chakrabarti
authors.affiliation: Department of Chemical, Biological And Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt lake, Kolkata 700106, India.
authors.forename: Mahua
authors.initials: M
authors.lastname: Ghosh
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002942:Circular Dichroism; D000067493:Dynamic Light Scattering; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D061848:Optical Imaging; D011487:Protein Conformation; D017510:Protein Folding / Q000528:radiation effects*; D055550:Protein Stability; D012485:Salmonella typhi / Q000737:chemistry*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins