Identification of a Functional Type IA Topoisomerase, LdTopIIIbeta, from Kinetoplastid Parasite Leishmania donovani.
Identification of a Functional Type IA Topoisomerase, LdTopIIIbeta, from Kinetoplastid Parasite Leishmania donovani.
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DOI：
10.4061/2011/230542
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发表时间：
2011-01-01
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影响因子：
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通讯作者：
Majumder, Hemanta K
中科院分区：
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作者：
Banerjee, Bijoylaxmi;Sen, Nilkantha;Majumder, Hemanta K
动质体DNA拓扑异构酶是一类DNA加工酶，它不仅解决了核DNA的拓扑问题，也解决了动质体DNA的拓扑问题。我们已经，第一次，确定了杜氏利什曼原虫同源的细菌和真核IA型拓扑异构酶III蛋白，并被称为LdTopIIIbeta。野生型和突变型LdTopIII β与缓慢生长的拓扑异构酶III突变酵母S.酿酒酵母揭示了拓扑异构酶III β蛋白的利什曼原虫对应物的功能保守性，327酪氨酸是活性位点氨基酸。LdTopIII β的C端缺失构建体不能抑制突变酵母的缓慢生长表型，表明LdTopIII β在体内的酶功能需要C端区域。两者合计，我们的研究表明LdTopIIibeta在寄生虫DNA加工的功能保护和可能的作用。
DNA topoisomerases of kinetoplastids represent a family of DNA processing enzymes that essentially solve the topological problems not only in nuclear DNA but also in kinetoplast DNA. We have, for the first time, identified a Leishmania donovani homologue of bacterial and eukaryotic IA type of topoisomerase III protein and termed as LdTopIIIbeta. Complementation study of wild-type and mutant LdTopIIIbeta with slow-growing topoisomerase III mutant yeast S. cerevisiae revealed the functional conservation of the leishmanial counterpart of topoisomerase IIIbeta protein, the 327 tyrosine being the active site amino acid. A C-terminal deletion construct of LdTopIIIbeta could not suppress the slow-growth phenotype of mutant yeast, indicating the requirement of C-terminal region for the enzyme function in vivo.LdTopIIIbeta localized inside the nucleus and kinetoplast of the parasite. Taken together, our study indicates functional conservation and possible role of LdTopIIIbeta in parasite DNA processing.