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Seal S, Chakraborty T, Polley S, Paul D, Banerjee N, Sinha D, Dutta A, Chatterjee S, Sau K, Ghosh Dastidar S, Sau S. Modeling and monitoring the effects of three partly conserved Ile residues in the dimerization domain of a Mip-like virulence factor from Escherichia coli. J Biomol Struct Dyn 2023:1-14. [PMID: 37902555 DOI: 10.1080/07391102.2023.2274978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/18/2023] [Indexed: 10/31/2023]
Abstract
FKBP22, an Escherichia coli-made peptidyl-prolyl cis-trans isomerase, has shown considerable homology with Mip-like virulence factors. While the C-terminal domain of this enzyme is used for executing catalytic function and binding inhibitor, the N-terminal domain is employed for its dimerization. To precisely determine the underlying factors of FKBP22 dimerization, its structural model, developed using a suitable template, was carefully inspected. The data show that the dimeric FKBP22, like dimeric Mip proteins, has a V-like shape. Further, it dimerizes using 40 amino acid residues including Ile 9, Ile 17, Ile 42, and Ile 65. All of the above Ile residues except Ile 9 are partly conserved in the Mip-like proteins. To confirm the roles of the partly conserved Ile residues, three FKBP22 mutants, constructed by substituting them with an Ala residue, were studied as well. The results together indicate that Ile 65 has little role in maintaining the dimeric state or enzymatic activity of FKBP22. Conversely, both Ile 17 and Ile 42 are essential for preserving the structure, enzymatic activity, and dimerization ability of FKBP22. Ile 42 in particular looks more essential to FKBP22. However, none of these two Ile residues is required for binding the cognate inhibitor. Additional computational studies also indicated the change of V-shape and the dimeric state of FKBP22 due to the Ala substitution at position 42. The ways Ile 17 and Ile 42 protect the structure, function, and dimerization of FKBP22 have been discussed at length.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Soham Seal
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | | | - Soumitra Polley
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | - Debarati Paul
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | | | - Debasmita Sinha
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | - Anindya Dutta
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | | | - Keya Sau
- Department of Biotechnology, Haldia Institute of Technology, Haldia, India
| | | | - Subrata Sau
- Department of Biological Sciences, Bose Institute, Kolkata, India
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Seal S, Polley S, Sau S. A staphylococcal cyclophilin carries a single domain and unfolds via the formation of an intermediate that preserves cyclosporin A binding activity. PLoS One 2019; 14:e0210771. [PMID: 30925148 PMCID: PMC6440624 DOI: 10.1371/journal.pone.0210771] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 03/18/2019] [Indexed: 12/22/2022] Open
Abstract
Cyclophilin (Cyp), a peptidyl-prolyl cis-trans isomerase (PPIase), acts as a virulence factor in many bacteria including Staphylococcus aureus. The enzymatic activity of Cyp is inhibited by cyclosporin A (CsA), an immunosuppressive drug. To precisely determine the unfolding mechanism and the domain structure of Cyp, we have investigated a chimeric S. aureus Cyp (rCyp) using various probes. Our limited proteolysis and the consequent analysis of the proteolytic fragments indicate that rCyp is composed of one domain with a short flexible tail at the C-terminal end. We also show that the urea-induced unfolding of both rCyp and rCyp-CsA is completely reversible and proceeds via the synthesis of at least one stable intermediate. Both the secondary structure and the tertiary structure of each intermediate appears very similar to those of the corresponding native protein. Conversely, the hydrophobic surface areas of the intermediates are comparatively less. Further analyses reveal no loss of CsA binding activity in rCyp intermediate. The thermodynamic stability of rCyp was also significantly increased in the presence of CsA, recommending that this protein could be employed to screen new CsA derivatives in the future.
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Affiliation(s)
- Soham Seal
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Soumitra Polley
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Subrata Sau
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
- * E-mail:
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Biswas A, Ghosh S, Sinha D, Dutta A, Seal S, Bagchi A, Sau S. Dimerization ability, denaturation mechanism, and the stability of a staphylococcal phage repressor and its two domains. Int J Biol Macromol 2019; 124:903-914. [DOI: 10.1016/j.ijbiomac.2018.11.263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 11/29/2022]
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