Padmanabhan, Prasad K and Mukherjee, Angana and Singh, Sushma and Chattopadhyaya, Swati and Gowri, Venkataraman S and Myler, Peter J and Srinivasan, Narayanaswamy and Madhubala, Rentala (2005) Glyoxalase I from Leishmania donovani: A potential target for anti-parasite drug. In: Biochemical and Biophysical Research Communications, 337 (4). pp. 1237-1248.
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Glyoxalases are involved in a ubiquitous detoxification pathway. In pursuit of a better understanding of the biological function of the enzyme. the recombinant glyoxalase I (LdGLOI) protein has been characterized from Leishmania donovani, the most important pathogenic Leishmania species that is responsible for visceral leishmaniasis. A 24 kDa protein was heterologously expressed in Escherichia coli. LdGLOI showed a marked substrate specificity for trypanothione hemithioacetal over glutathione hemithioacetal. Antiserum against recombinant LdGLOI protein could detect a band of anticipated size similar to 16 kDa in promastigote extracts. Several inhibitors of human GLOI showed that they are weak inhibitors of L. donovani growth. Overexpression of GLOI gene in L. donovani using Leishmania expression vector psp alpha hygro alpha, we detected elevated expression of GLOI RNA and protein. Comparative modelling of the 3-D structure of LDGLOI shows that substrate-binding region of the model involves important differences compared to the homologues, such as E coli, specific to glutathione. Most notably a substrate-binding loop of LDGLOI is characterized by a deletion of five residues compared to the E coli homologue. Further, a critical Arg in the E coli variant at the substrate-binding site is replaced by Tyr in LDGLOI These major differences result in entirely different shapes of the substrate-binding loop and presence of very different chemical groups in the substrate-binding site of LDGLOI compared to E coli homologue suggesting an explanation for the difference in the substrate specificity. Difference in the substrate specificity of the human and LDGLOI enzyme could be exploited for structure-based drug designing of selective inhibitors against the parasite.
|Item Type:||Journal Article|
|Additional Information:||Copyright for this article belongs to Elsevier.|
|Keywords:||Leishmania donovani;Recombinant glyoxalase I;Overexpression;Inhibitors;Structural analysis|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||15 Dec 2005|
|Last Modified:||19 Sep 2010 04:22|
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