Amino Acid Residues of Leishmania donoVani Cyclophilin Key to Interaction with Its Adenosine Kinase: Biological Implications
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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| Title |
Amino Acid Residues of Leishmania donoVani Cyclophilin Key to Interaction with Its Adenosine Kinase: Biological Implications
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| Creator |
Sen, Banibrata
Venugopal, V Chakraborty, Anutosh Datta, Rupak Dolai, Subhankar Banerjee, Rahul Datta, Alok K |
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| Subject |
Structural Biology & Bioinformatics
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| Description |
Cyclophilins (CyPs), by interacting with a variety of proteins, often modulate their biological
activities and thus have been implicated in several cellular functions. However, mechanisms that determine
such interactions are poorly understood. We earlier reported that an endoplasmic reticulum (ER)-located
cyclophilin (LdCyP) from the purine auxotrophic parasitic protozoan Leishmania donoVani reactivated
its adenosine kinase (AdK). The AdK-reactivating property of LdCyP was however abolished at high
ionic strength but not by nonionic detergents. Modeling of LdCyP, based on its crystal structure solved
at 1.97 Å resolution, revealed several solvent-exposed hydrophobic and charged residues. Mutagenesis of
several of such solvent-exposed residues was performed and their corresponding activities with regard to
their (i) AdK reactivation property, (ii) ability to form complex with the enzyme, (iii) capacity to induce
red shift in the intrinsic tryptophan fluorescence maxima of AdK, and (iv) efficiency to withdraw the
ADP inhibition from the AdK-mediated reaction were compared to the wild-type protein. Results indicated
that while the replacement of R147 with either A or D severely impaired all of the above characteristics
displayed by the wild-type LdCyP, the effect of mutating K114 and K153 was although relatively less
but nevertheless noticeable. Alteration of other exposed hydrophobic and charged residues apparently did
not have any discernible effect. Under the condition of cellular stress, the ER-located LdCyP is released
into the cytoplasm with concomitant increase both in the specific activity of the cytosol-resident AdK
and the uptake of radiolabeled Ado into the cells. These experiments, besides demonstrating the importance
of the positive charge, identified R147 as the most crucial residue in the LdCyP-AdK interaction and
provide evidence for the stress-induced retrograde translocation of LdCyP from the ER to the cytoplasm.
A possible implication of this interaction in the life cycle of the parasite is proposed.
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| Date |
2007
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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/302/1/BIOCHEMISTRY%2C46(26)_7832%2D7843[65].pdf
Sen, Banibrata and Venugopal, V and Chakraborty, Anutosh and Datta, Rupak and Dolai, Subhankar and Banerjee, Rahul and Datta, Alok K (2007) Amino Acid Residues of Leishmania donoVani Cyclophilin Key to Interaction with Its Adenosine Kinase: Biological Implications. Biochemistry , 46. pp. 7832-7843. |
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| Relation |
http://dx.doi.org/10.1021/bi602625h
http://www.eprints.iicb.res.in/302/ |
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