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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, Banerjee N, Mahato R, Kundu T, Sinha D, Chakraborty T, Sinha D, Sau K, Chatterjee S, Sau S. Serine 106 preserves the tertiary structure, function, and stability of a cyclophilin from Staphylococcus aureus. J Biomol Struct Dyn 2023; 41:1479-1494. [PMID: 34967275 DOI: 10.1080/07391102.2021.2021992] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SaCyp, a staphylococcal cyclophilin involved in both protein folding and pathogenesis, has a Ser residue at position 106 and a Trp residue at position 136. While Ser 106 of SaCyp aligned with a cyclosporin A (CsA) binding Ala residue, its Trp 136 aligned with a Trp or a Phe residue of most other cyclophilins. To demonstrate the exact roles of Ser 106 and Trp 136 in SaCyp, we have elaborately studied rCyp[S106A] and rCyp[W136A], two-point mutants of a recombinant SaCyp (rCyp) harboring an Ala substitution at positions 106 and 136, respectively. Of the mutants, rCyp[W136A] showed the rCyp-like CsA binding affinity and peptidyl-prolyl cis-trans isomerase (PPIase) activity. Conversely, the PPIase activity, CsA binding affinity, stability, tertiary structure, surface hydrophobicity, and Trp accessibility of rCyp[S106A] notably differed from those of rCyp. The computational experiments also reveal that the structure, dimension, and fluctuation of SaCyp are not identical to those of SaCyp[S106A]. Furthermore, Ser at position 106 of SaCyp, compared to Ala at the same position, formed a higher number of non-covalent bonds with CsA. Collectively, Ser 106 is an indispensable residue for SaCyp that keeps its tertiary structure, function, and stability intact.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Soham Seal
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Nilanjan Banerjee
- Department of Biophysics, Bose Institute, Kolkata, West Bengal, India
| | - Rohit Mahato
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Tanmoy Kundu
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Debabrata Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | | | - Debasmita Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Keya Sau
- Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India
| | | | - Subrata Sau
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
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Seal S, Chowdhury N, Biswas R, Chakraborty T, Sinha D, Bagchi A, Sau S. Removal of an atypical region from a staphylococcal cyclophilin affects its structure, function, stability, and shape. Int J Biol Macromol 2020; 151:1287-1298. [DOI: 10.1016/j.ijbiomac.2019.10.175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/15/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022]
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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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