Cellular and molecular actions of dinitroaniline and phosphorothioamidate herbicides on Plasmodium falciparum: Tubulin as a specific antimalarial target (original) (raw)
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Faktori eksperimental'noi evolucii organizmiv, 2020
Aim. Identification of amino acid residues participating in specific binding of dinitroaniline and phosphorothioamidate compounds with α-tubulin in Plasmodium falciparum. Methods. Protein structure modelling, protein structure optimization using molecular dynamics method, ligand-protein docking, alanine scanning mutagenesis. Results. Molecular docking of canonical compounds and alanine scanning mutagenesis, indicate two key (Arg2, Val250) and one minor (Glu3) residues involved in binding of both - dinitroaniline and phosphorothioamidate compounds. At the same time, it was revealed two minor residues (Asp251, Glu254) interacting only with some members of dinitroaniline grope. Conclusions. It was identified amino acid residues predetermining existence of joint site and similar interaction of α-tubulin with dinitroani-line and phosphorothioamidate compounds in P. falciparum. Keywords: malaria, Plasmodium, α-tubulin, molecular interaction, dinitroanilines compounds, phosphorothioamidate...
International Journal of Molecular Sciences
Dinitroanilines are chemical compounds with high selectivity for plant cell α-tubulin in which they promote microtubule depolymerization. They target α-tubulin regions that have diverged over evolution and show no effect on non-photosynthetic eukaryotes. Hence, they have been used as herbicides over decades. Interestingly, dinitroanilines proved active on microtubules of eukaryotes deriving from photosynthetic ancestors such as Toxoplasma gondii and Plasmodium falciparum, which are responsible for toxoplasmosis and malaria, respectively. By combining differential in silico screening of virtual chemical libraries on Arabidopsis thaliana and mammal tubulin structural models together with cell-based screening of chemical libraries, we have identified dinitroaniline related and non-related compounds. They inhibit plant, but not mammalian tubulin assembly in vitro, and accordingly arrest A. thaliana development. In addition, these compounds exhibit a moderate cytotoxic activity towards T...
Dinitroanilines Bind -Tubulin to Disrupt Microtubules
Molecular Biology of the Cell, 2004
Protozoan parasites are remarkably sensitive to dinitroanilines such as oryzalin, which disrupt plant but not animal microtubules. To explore the basis of dinitroaniline action, we isolated 49 independent resistant Toxoplasma gondii lines after chemical mutagenesis. All 23 of the lines that we examined harbored single point mutations in ␣-tubulin. These point mutations were sufficient to confer resistance when transfected into wild-type parasites. Several mutations were in the M or N loops, which coordinate protofilament interactions in the microtubule, but most of the mutations were in the core of ␣-tubulin. Docking studies predict that oryzalin binds with an average affinity of 23 nM to a site located beneath the N loop of Toxoplasma ␣-tubulin. This binding site included residues that were mutated in several resistant lines. Moreover, parallel analysis of Bos taurus ␣-tubulin indicated that oryzalin did not interact with this site and had a significantly decreased, nonspecific affinity for vertebrate ␣-tubulin. We propose that the dinitroanilines act through a novel mechanism, by disrupting M-N loop contacts. These compounds also represent the first class of drugs that act on ␣-tubulin function.
Synthesis, Structural Determination, and Pharmacology of Putative Dinitroaniline Antimalarials
A series of novel, homologous compounds possessing the general formula N 1-N n-bis(2,6-dinitro-4-trifluormethylphenyl)-1,n-diamino alkanes (where n = 4, 6, 10 or 12), were designed to probe inter-and intra-binding site dimensions in malarial parasite (Plasmodium) tubulin. Various crystal structures, including chloralin and trifluralin, an isopropyl dimer, and 2,6-dinitro-4-trifluoromethyl-phenylamine, were determined. Dinitroanilines, when soluble, were evaluated both in culture and in vivo. Trifluralin was up to 2-fold more active than chloralin against cultured parasites. The isopropyl dimer was water soluble (> 5 mM) and revealed activity superior to that of chloralin in culture. The effects of selected dinitroanilines upon the mitotic microtubular structures of Plasmodium, the putative target of these dinitroanilines, were also determined. Electronic properties of the molecules were calculated using DFT (B3LYP/6-31 + G* level) to ascertain whether incorporation of such a pharmacophore could allow both QSAR and rational development of more selectively toxic antiparasitic agents.
Faktori eksperimental'noi evolucii organizmiv
Aim. To evaluate polymorphism of dinitroaniline/phosphorothioamidate binding site in α-tubulin molecules from Plasmodium species (P. falciparum, P. vivax, P. ovale, and P. malariae) and strains discovered in India. Methods. Literature and database search. Bioinformatical comparison of protein sequences and structures. Multiple sequence alignment, phylogenetic profiling, protein structure modeling, etc. Results. 14 complete sequences of α-tubulin from four Plasmodium species were selected from UniProtKB. Despite certain differences in complete sequences of α-tubulin molecules from different Plasmodium species and strains, sites of their interaction with dinitroaniline and phosphorothioamidate compounds were shown to be identical. Conclusions. Complete identity of dinitroaniline/phosphorothioamidate binding sites in all studied isotypes of α-tubulin molecules from P. falciparum, P. vivax, P. ovale, and P. malariae was confirmed. This suggests identity of the ligand-protein interaction...
Dinitroanilines bind α-tubulin to disrupt microtubules
2004
Protozoan parasites are remarkably sensitive to dinitroanilines such as oryzalin, which disrupt plant but not animal microtubules. To explore the basis of dinitroaniline action, we isolated 49 independent resistant Toxoplasma gondii lines after chemical mutagenesis. All 23 of the lines that we examined harbored single point mutations in ␣-tubulin. These point mutations were sufficient to confer resistance when transfected into wild-type parasites. Several mutations were in the M or N loops, which coordinate protofilament interactions in the microtubule, but most of the mutations were in the core of ␣-tubulin. Docking studies predict that oryzalin binds with an average affinity of 23 nM to a site located beneath the N loop of Toxoplasma ␣-tubulin. This binding site included residues that were mutated in several resistant lines. Moreover, parallel analysis of Bos taurus ␣-tubulin indicated that oryzalin did not interact with this site and had a significantly decreased, nonspecific affinity for vertebrate ␣-tubulin. We propose that the dinitroanilines act through a novel mechanism, by disrupting M-N loop contacts. These compounds also represent the first class of drugs that act on ␣-tubulin function.
Dinitroaniline herbicides against protozoan parasites: the case of Trypanosoma cruzi
Trends in Parasitology, 2001
The drugs presently in use against Chagas disease are very toxic, inducing a great number of side effects. Alternative treatments are necessary, not only for Chagas disease but also for other diseases caused by protozoan parasites where current drugs pose toxicity problems. The plant microtubule inhibitor trifluralin has previously been tested with success against Leishmania, Trypanosoma brucei and several other protozoan parasites. Trypanosoma cruzi, the causative agent of Chagas disease, is also sensitive to the drug. This sensitivity has been correlated with the deduced amino acid sequences of α αand β β-tubulin of T. cruzi as compared with plant, mammal and other parasite sequences.