Topoisomerase I Gene Mutations at F270 in the Large Subunit and N184 in the Small Subunit Contribute to the Resistance Mechanism of the Unicellular Parasite Leishmania donovani towards 3,3�-Diindolylmethane
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
Topoisomerase I Gene Mutations at F270 in the Large Subunit and
N184 in the Small Subunit Contribute to the Resistance Mechanism
of the Unicellular Parasite Leishmania donovani towards
3,3�-Diindolylmethane
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| Creator |
Roy, Amit
Bose Dasgupta, Somdeb Ganguly, Agneyo Jaisankar , P Majumder, Hemanta K |
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| Subject |
Infectious Diseases and Immunology
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| Description |
3,3�-Diindolylmethane (DIM), a novel poison targeting Leishmania donovani topoisomerase I (LdTOP1LS),
induces programmed cell death in Leishmania parasites. The development of resistant parasites by adaptation
with increasing concentrations of DIM generates random mutations in LdTOP1LS. Single-nucleotide mutations
result in the amino acid substitutions F270L and K430N in the large subunit and N184S in the small
subunit of the enzyme. DIM failed to inhibit the catalytic activity of the recombinant mutant enzyme
(LdTOP1DRLS). Transfection studies of the mutant genes showed that the mutated topoisomerase I confers
DIM resistance on wild-type Leishmania parasites. Site-directed mutagenesis studies revealed that a substantial
level of resistance is conferred by the F270L mutation alone; however, all three mutations (F270L, K430N,
and N184S) together are required to reach a higher-resistance phenotype. DIM fails to stabilize the topoisomerase
I–DNA covalent complexes in the F270 mutant. Moreover, DIM cannot interfere with the religation step
in the catalytic cycle of the recombinant F270L mutant enzyme. Taken together, these findings identify novel
mutations in topoisomerase I that hinder its interaction with DNA, thereby modulating enzyme catalysis and
conferring resistance to DIM. These studies advance our understanding of the mechanism of cell poisoning by
DIM and suggest a specific modification of the drug that may improve its efficacy.
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| Publisher |
American Society for Microbiology
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| Date |
2009
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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/130/1/ANTIMICROBIAL_AGENTS_AND_CHEMOTHERAPY%2C_53_(6)%2C_2589%2D2598%2C_2009[61].pdf
Roy, Amit and Bose Dasgupta, Somdeb and Ganguly, Agneyo and Jaisankar , P and Majumder, Hemanta K (2009) Topoisomerase I Gene Mutations at F270 in the Large Subunit and N184 in the Small Subunit Contribute to the Resistance Mechanism of the Unicellular Parasite Leishmania donovani towards 3,3�-Diindolylmethane. Antimicrobial Agents and Chemotherapy, 53 (6). pp. 2589-2598. |
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| Relation |
http://dx.doi.org/10.1128/AAC.01648-08
http://www.eprints.iicb.res.in/130/ |
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