Characterization of an unusual cold shock protein from Staphylococcus aureus |
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Authors: | Palas K. Chanda Amitava Bandhu Biswanath Jana Rajkrishna Mondal Tridib Ganguly Keya Sau Chia Y. Lee Gopal Chakrabarti Subrata Sau Dr. |
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Affiliation: | 1. Department of Biochemistry, Bose Institute, Kolkata, India;2. Department of Biological Sciences, IISER, Kolkata, India;3. School of Biotechnology and Life Sciences, Haldia Institute of Technology, Haldia, India;4. Department of Microbiology and Immunology, UAMS, Little Rock, AR, USA;5. Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, India |
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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. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
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Keywords: | Staphylococcus aureus Cold shock protein (Csp) CspC Single‐stranded (ss) DNA GdmCl (guanidium hydrochloride) |
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