A Single-domain Cyclophilin from Leishmania donovani Reactivates Soluble Aggregates of Adenosine Kinase by Isomerase-independent Chaperone Function
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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Title |
A Single-domain Cyclophilin from Leishmania donovani Reactivates
Soluble Aggregates of Adenosine Kinase by Isomerase-independent
Chaperone Function
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Creator |
Chakraborty, Anutosh
Das, Ishita Datta, Rupak Sen, Banibrata Bhattacharyya, Debasish Mandal, Chhabinath Datta, Alok K |
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Subject |
Drug Development/Diagnostics & Biotechnology
Infectious Diseases and Immunology |
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Description |
Disaggregation and reactivation of aggregated proteins
by chaperones is well established. However, little
is known regarding such kind of function of single-domain
small cyclophilins (CyPs). Here we demonstrate
that, with increasing concentrations, fully active adenosine
kinase (AdK) of Leishmania donovani tends to
form soluble aggregates, resulting in inactivation. Using
this inactive enzyme as the substrate, it is shown that a
CyP from L. donovani (LdCyP) alone can cause complete
disaggregation, leading to reactivation of the enzyme.
The reactivating ability of LdCyP remains unaffected
even in the presence of cyclosporin A and macromolecular
crowding agents. The reactivation occurs noncatalytically
and is reversible. A truncated LdCyP, devoid of
88 amino acids from the N terminus, is found to be required
in near stoichiometric proportion to reactivate
AdK, suggesting essentiality of the C-terminal region.
Gel filtration and light-scattering experiments together
with protein cross-linking studies revealed that both
full-length LdCyP and the truncated form directly interact
with AdK and convert oligomeric forms of the enzyme
to monomeric state. Homology modeling studies
suggest that the exposed hydrophobic residues of Ld-
CyP, by interacting with solvent-accessible hydrophobic
surface of AdK, pull apart its aggregated inactive
oligomers to functional monomers. Clearly, the results
are consistent with the interpretation that the higher
efficiency of the truncated LdCyP is most likely due to
increased exposure of the hydrophobic residues on its
surface. These observations, besides establishing L. donovani
AdK as one of the model enzymes to study aggregation-
disaggregation of proteins, raise the possibility
that single-domain small CyPs, under physiological conditions,
may regulate the activity of aggregation-prone
proteins by ensuring their disaggregation.
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Publisher |
American Society for Biochemistry and Molecular Biology
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Date |
2002
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://www.eprints.iicb.res.in/544/1/JOURNAL_OF_BIOLOGICAL_CHEMISTRY__277(49)_47451%2D47460_;2002[1].pdf
Chakraborty, Anutosh and Das, Ishita and Datta, Rupak and Sen, Banibrata and Bhattacharyya, Debasish and Mandal, Chhabinath and Datta, Alok K (2002) A Single-domain Cyclophilin from Leishmania donovani Reactivates Soluble Aggregates of Adenosine Kinase by Isomerase-independent Chaperone Function. The Journal of Biological Chemistry, 277 (49). pp. 47451-47460. |
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Relation |
http://dx.doi.org/10.1074/jbc.M204827200
http://www.eprints.iicb.res.in/544/ |
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