Reassessment of the Catalytic activity and substrate specificity of FKBP35 from Plasmodium Knowlesi using Protease-Free Assay
FK506-binding protein35 of Plasmodium knowlesi (Pk-FKBP35) is a member of peptidyl prolyl cis-trans isomerase (PPIase) and is considered as a promising avenue of antimalarial drug target development. This protein is organized into the N-terminal domain responsible for PPIase catalytic activity follo...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Borneo International Journal of Biotechnology (BIJB)
2020
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/27448/1/Reassessment%20of%20the%20Catalytic%20activity%20and%20substrate%20specificity%20of%20FKBP35%20from%20Plasmodium%20Knowlesi%20using%20Protease-Free%20Assay%20abstract.pdf https://eprints.ums.edu.my/id/eprint/27448/2/Reassessment%20of%20the%20Catalytic%20activity%20and%20substrate%20specificity%20of%20FKBP35%20from%20Plasmodium%20Knowlesi%20using%20Protease-Free%20Assay%20FULLTEXT.pdf https://eprints.ums.edu.my/id/eprint/27448/ https://jurcon.ums.edu.my/ojums/index.php/bijb/article/view/2602 https://doi.org/10.51200/bijb.vi.2602 |
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| Summary: | FK506-binding protein35 of Plasmodium knowlesi (Pk-FKBP35) is a member of peptidyl prolyl cis-trans isomerase (PPIase) and is considered as a promising avenue of antimalarial drug target development. This protein is organized into the N-terminal domain responsible for PPIase catalytic activity followed and the tetratricopeptide repeat domain for its dimerization. The protease-coupling and protease-free assays are known to be the common methods for investigating the catalytic properties of PPIase. Earlier, the protease-coupling assay was used to confirm the catalytic activity of Pk-FKBP35 in accelerating cis-trans isomerization of the peptide substrate. This report is aimed to re-assess the catalytic and substrate specificity of Pk-FKBP35 using an alternative method of a protease-free assay. The result indicated that while Pk-FKBP35 theoretically contained many possible cleavage sites of chymotrypsin, experimentally, the catalytic domain was relatively stable from chymotrypsin. Furthermore, under protease-free assay, Pk-FKBP35 also demonstrated remarkable PPIase catalytic activity with kcat/KM of 4.5 + 0.13 × 105 M−1 s−1, while the kcat/KM of active site mutant of D55A is 0.81 + 0.05 × 105 M−1 s−1. These values were considered comparable to kcat/KM obtained from the protease-coupling assay. Interestingly, the substrate specificities of Pk-FKBP35 obtained from both methods are also similar, with the preference of Pk-FKBP35 towards Xaa at P1 position was Leu>Phe>Lys>Trp>Val>Ile>His>Asp>Ala>Gln>Glu. Altogether, we proposed that protease-free and protease-coupling assays arereliable for Pk-FKBP35. |
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