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Tryparedoxin peroxidase of Leishmania braziliensis: homology modeling and inhibitory effects of flavonoids for anti-leishmanial activity.

ABSTRACT: Inhibition of the Tryparedoxin peroxidase interaction has been becomes a new therapeutic strategy in leishmaniasis. Docking analysis was carried out to study the effects of quercetin and taxifolin on Tryparedoxin Peroxidase (TryP). Tryparedoxin peroxidase of Trypanosomatidae functions as antioxidants through their Peroxidase and peroxynitrite reductase activities. The 3D models of Tryparedoxin Peroxidase of Leishmania braziliensis (L. braziliensis TryP) was modeled using the template Tryparedoxin Peroxidase I from Leishmania Major (L. Major TryPI) (PDB ID: 3TUE). Further, we evaluated for TryP inhibitory activity of flavonoids such as quercetin and taxifolin using in silico docking studies. Docking results showed the binding energies of - 11.8601and -8.0851 for that quercetin and taxifolin respectively. Flavonoids contributed better L. braziliensis TryP inhibitory activity because of its structural parameters. Thus, from our in silico studies we identify that quercetin and taxifolin posses anti-leishmanial acitivities mediated through TryP inhibition mechanism.

SUBMITTER: Gundampati RK

PROVIDER: S-EPMC4110426 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Tryparedoxin peroxidase of Leishmania braziliensis: homology modeling and inhibitory effects of flavonoids for anti-leishmanial activity.

Gundampati Ravi Kumar RK Sahu Shraddha S Shukla Ankita A Pandey Rajesh Kumar RK Patel Monika M Banik Rathindra Mohan RM Jagannadham Medicherla Venkata MV

Bioinformation 20140630 6

Inhibition of the Tryparedoxin peroxidase interaction has been becomes a new therapeutic strategy in leishmaniasis. Docking analysis was carried out to study the effects of quercetin and taxifolin on Tryparedoxin Peroxidase (TryP). Tryparedoxin peroxidase of Trypanosomatidae functions as antioxidants through their Peroxidase and peroxynitrite reductase activities. The 3D models of Tryparedoxin Peroxidase of Leishmania braziliensis (L. braziliensis TryP) was modeled using the template Tryparedoxi ...[more]

PMID: 25097378

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Project description:BackgroundTryparedoxin peroxidase (TXNPx) participates in defence against oxidative stress as an antioxidant by metabolizing hydrogen peroxide into water molecules. Reports suggest that drug-resistant parasites may increase the levels of TXNPx and other enzymes, thereby protecting them against oxidative stress.MethodsIn this study, the gene encoding cytosolic TXNPx (cTXNPx) was characterized in lines of Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum that are susceptible and resistant to potassium antimony tartrate (Sb(III)). We investigated the levels of mRNA and genomic organization of the cTXNPx gene. In addition, we transfected the Leishmania lines with the cTXNPx gene and analysed the susceptibility of transfected parasites to Sb(III) and to hydrogen peroxide (H2O2).ResultsNorthern blot and real-time reverse transcriptase polymerase chain reaction analyses revealed that the level of TXNPx mRNA was approximately 2.5-fold higher in the Sb(III)-resistant L. braziliensis line than in the parental line. In contrast, no significant difference in cTXNPx mRNA levels between the L. infantum lines was observed. Southern blot analyses revealed that the cTXNPx gene is not amplified in the genome of the Sb(III)-resistant Leishmania lines analysed. Functional analysis of cTXNPx was performed to determine whether overexpression of the enzyme in L. braziliensis and L. infantum lines would change their susceptibility to Sb(III). Western blotting analysis showed that the level of cTXNPx was 2 to 4-fold higher in transfected clones compared to non-transfected cells. Antimony susceptibility test (EC50 assay) revealed that L. braziliensis lines overexpressing cTXNPx had a 2-fold increase in resistance to Sb(III) when compared to the untransfected parental line. In addition, these clones are more tolerant to exogenous H2O2 than the untransfected parental line. In contrast, no difference in Sb(III) susceptibility and a moderate index of resistance to H2O2 was observed in L. infantum clones overexpressing cTXNPx.ConclusionOur functional analysis revealed that cTXNPx is involved in the antimony-resistance phenotype in L. braziliensis.

Project description:Leishmaniasis is a neglected disease caused by Leishmania, an intracellular protozoan parasite which possesses a unique thiol metabolism based on trypanothione. Trypanothione is used as a source of electrons by the tryparedoxin/tryparedoxin peroxidase system (TXN/TXNPx) to reduce the hydroperoxides produced by macrophages during infection. This detoxification pathway is not only unique to the parasite but is also essential for its survival; therefore, it constitutes a most attractive drug target. Several forms of TXNPx, with very high sequence identity to one another, have been found in Leishmania strains, one of which has been used as a component of a potential anti-leishmanial polyprotein vaccine. The structures of cytosolic TXN and TXNPx from L. major (LmTXN and LmTXNPx) offer a unique opportunity to study peroxide reduction in Leishmania parasites at a molecular level, and may provide new tools for multienzyme inhibition-based drug discovery. Structural analyses bring out key structural features to elucidate LmTXN and LmTXNPx function. LmTXN displays an unusual N-terminal ?-helix which allows the formation of a stable domain-swapped dimer. In LmTXNPx, crystallized in reducing condition, both the locally unfolded (LU) and fully folded (FF) conformations, typical of the oxidized and reduced protein respectively, are populated. The structural analysis presented here points to a high flexibility of the loop that includes the peroxidatic cysteine which facilitates Cys52 to form an inter-chain disulfide bond with the resolving cysteine (Cys173), thereby preventing over-oxidation which would inactivate the enzyme. Analysis of the electrostatic surface potentials of both LmTXN and LmTXNPx unveils the structural elements at the basis of functionally relevant interaction between the two proteins. Finally, the structural analysis of TXNPx allows us to identify the position of the epitopes that make the protein antigenic and therefore potentially suitable to be used in an anti-leishmanial polyprotein vaccine.

Dataset Information

Tryparedoxin peroxidase of Leishmania braziliensis: homology modeling and inhibitory effects of flavonoids for anti-leishmanial activity.

Publications

Tryparedoxin peroxidase of Leishmania braziliensis: homology modeling and inhibitory effects of flavonoids for anti-leishmanial activity.

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