Estudio de la relación estructura-función y acción de moléculas efectoras sobre la hipoxantina fosforribosiltransferasa de trypanosoma cruzi
This study investigates the structure-function relationship and the effects of a family of ligands on T. cruzi hypoxanthine phosphoribosyltransferase (TcHPRT). This enzyme has been proposed as a potential target for drugs aimed at treating parasitic diseases.\nHere we present an in-depth analysis of...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
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Facultad de Farmacia y Bioquímica
2018
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=posgraafa&cl=CL1&d=HWA_2603 http://repositoriouba.sisbi.uba.ar/gsdl/collect/posgraafa/index/assoc/HWA_2603.dir/2603.PDF |
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| Sumario: | This study investigates the structure-function relationship and the effects of a family of ligands on T. cruzi hypoxanthine phosphoribosyltransferase (TcHPRT). This enzyme has been proposed as a potential target for drugs aimed at treating parasitic diseases.\nHere we present an in-depth analysis of the role of the C-terminal region (CTR) in the consolidation of the quaternary structure of the protein and its consequence on the enzymatic activity. TcHPRT in solution naturally adopts a tetrameric arrangement, which dissociates into dimers after proteolytic removal of the CTR, as predicted by our crystallographic data. As a result of this process, the dimer shows somewhat increased activity.\nWe also present a kinetic analysis of the TcHPRT activity, which is fully consistent with its inhibition induced by a set of bisphosphonates. The bimodal effect observed at low and at high concentrations of these compounds agrees well with our original proposal of a cooperative model for the activity of this oligomeric enzyme. The observed effects become more evident for the tetramer than for the dimer.\nCultures of epimastigotes and trypomastigotes exposed to bisphosphonates show growth inhibition, supporting the results on the free enzyme. Strikingly, the inhibitory effect is essentially null when assayed against human HPRT.\nWe hope that this new molecular and cellular knowledge will bear high relevance for the design of innovative parasite-targeted therapeutics. |
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