title: Characterization of an unusual cold shock protein from Staphylococcus aureus.
abstract: Of the three cold shock proteins expressed by Staphylococcus aureus, CspC is induced poorly by cold but strongly by various antibiotics and toxic chemicals. Using a purified CspC, here we demonstrate that it exists as a monomer in solution, possesses primarily β-sheets, and bears substantial structural similarity with other bacterial Csps. Aggregation of CspC was initiated rapidly at temperatures above 40 °C, whereas, the Gibbs free energy of stabilization of CspC at 0 M GdmCl was estimated to be +1.6 kcal mol(-1), indicating a less stable protein. Surprisingly, CspC showed stable binding with ssDNA carrying a stretch of more than three thymine bases and binding with such ssDNA had not only stabilized CspC against proteolytic degradation but also quenched the fluorescence intensity from its exposed Trp residue. Analysis of quenching data indicates that each CspC molecule binds with ∼5 contiguous thymine bases of the above ssDNA and binding is cooperative in nature.
authors.affiliation: Department of Biochemistry, Bose Institute, Kolkata, India.
authors.forename: Palas K
authors.initials: PK
authors.lastname: Chanda
authors.forename: Amitava
authors.initials: A
authors.lastname: Bandhu
authors.forename: Biswanath
authors.initials: B
authors.lastname: Jana
authors.forename: Rajkrishna
authors.initials: R
authors.lastname: Mondal
authors.forename: Tridib
authors.initials: T
authors.lastname: Ganguly
authors.forename: Keya
authors.initials: K
authors.lastname: Sau
authors.forename: Chia Y
authors.initials: CY
authors.lastname: Lee
authors.forename: Gopal
authors.initials: G
authors.lastname: Chakrabarti
authors.forename: Subrata
authors.initials: S
authors.lastname: Sau
mesh_terms: D000900:Anti-Bacterial Agents / Q000633:toxicity; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D002942:Circular Dichroism; D003080:Cold Temperature; D004277:DNA, Single-Stranded / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D055550:Protein Stability; D013211:Staphylococcus aureus / Q000378:metabolism* / Q000528:radiation effects*; D013941:Thymine / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C088099:CspC protein, bacteria; D004277:DNA, Single-Stranded; D006360:Heat-Shock Proteins; D013941:Thymine
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