Title

Identification and characterization of a cyclosporin binding cyclophillin from Staphylococcus aureus
Newman

Authors

Soumitra Polley¹, Soham Seal¹, Avisek Mahapa², Biswanath Jana¹, Anindya Biswas¹, Sukhendu Mandal¹, Debabrata Sinha¹, Keya Sau² and Subrata Sau^1*

Affiliation

¹Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India;

²Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India;

Email

subratasau@gmail.com

Article Type

Hypothesis

Date

Received December 28, 2016; Accepted February 4, 2017; Published March 31, 2017

Cyclophilins, a class of peptidyl-prolyl cis-trans isomerase (PPIase) enzymes, are inhibited by cyclosporin A (CsA), an immunosuppressive drug. Staphylococcus aureus Newman, a pathogenic bacterium, carries a gene for encoding a putative cyclophilin (SaCyp). SaCyp shows significant homology with other cyclophilins at the sequence level. A three-dimensional model structure of SaCyp harbors a binding site for CsA. To verify whether SaCyp possess both the PPIase activity and the CsA binding ability, we have purified and investigated a recombinant SaCyp (rCyp) using various in vitro tools. Our RNase T1 refolding assay indicates that rCyp has a substantial extent of PPIase activity. rCyp that exists as a monomer in the aqueous solution is truly a cyclophilin as its catalytic activity specifically shows sensitivity to CsA. rCyp appears to bind CsA with a reasonably high affinity. Additional investigations reveal that binding of CsA to rCyp alters its structure and shape to some extent. Both rCyp and rCyp-CsA are unfolded via the formation of at least one intermediate in the presence of guanidine hydrochloride. Unfolding study also indicates that there is substantial extent of thermodynamic stabilization of rCyp in the presence of CsA as well. The data suggest that rCyp may be exploited to screen the new antimicrobial agents in the future.

Keywords

Staphylococcus aureus, cyclophilin, cyclosporin A, GdnCl, unfolding, intermediate, and stability

Citation

Polley et al. Bioinformation 13(3): 78-85 (2017)

Edited by

P Kangueane

ISSN

0973-2063

Publisher

Biomedical Informatics

License

This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. This is distributed under the terms of the Creative Commons Attribution License.