CSIR Central

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

View Archive Info
 
 
Field Value
 
Title A Single-domain Cyclophilin from Leishmania donovani Reactivates Soluble Aggregates of Adenosine Kinase by Isomerase-independent Chaperone Function
 
Creator Chakraborty, Anutosh
Das, Ishita
Datta, Rupak
Sen, Banibrata
Bhattacharyya, Debasish
Mandal, Chhabinath
Datta, Alok K
 
Subject Drug Development/Diagnostics & Biotechnology
Infectious Diseases and Immunology
 
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.
 
Publisher American Society for Biochemistry and Molecular Biology
 
Date 2002
 
Type Article
PeerReviewed
 
Format application/pdf
 
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.
 
Relation http://dx.doi.org/10.1074/jbc.M204827200
http://www.eprints.iicb.res.in/544/