Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery
Giardiasis is a diarrheal disease caused by the unicellular parasite Giardia intestinalis, for which metronidazole is the main treatment option. The parasite is dependent on exogenous deoxyribonucleosides for DNA replication and thus is also potentially vulnerable to deoxyribonucleoside analogs. Her...
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| Formato: | Artículo |
| Lenguaje: | Español |
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American Society for Biochemistry and Molecular Biology Inc.
2022
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| Acceso en línea: | http://pa.bibdigital.ucc.edu.ar/3213/1/A_Luj%C3%A1n_Saura_Luj%C3%A1n.pdf |
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I38-R144-32132025-04-10T21:00:45Z http://pa.bibdigital.ucc.edu.ar/3213/ Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery Krakovka, Sascha Ranjbarian, Farahnaz Luján, Lucas A. Saura, Alicia Larsen, Nicolai B. Jiménez-González, Alejandro Reggenti, Anna Luján, Hugo Daniel Svärd, Staffan G. Hofer, Anders R Medicina (General) RZ Otros sistemas de la medicina Giardiasis is a diarrheal disease caused by the unicellular parasite Giardia intestinalis, for which metronidazole is the main treatment option. The parasite is dependent on exogenous deoxyribonucleosides for DNA replication and thus is also potentially vulnerable to deoxyribonucleoside analogs. Here, we characterized the G. intestinalis thymidine kinase, a divergent member of the thymidine kinase 1 family that consists of two weakly homologous parts within one polypeptide. We found that the recombinantly expressed enzyme is monomeric, with 100-fold higher catalytic efficiency for thymidine compared to its second-best substrate, deoxyuridine, and is furthermore subject to feedback inhibition by dTTP. This efficient substrate discrimination is in line with the lack of thymidylate synthase and dUTPase in the parasite, which makes deoxy-UMP a dead-end product that is potentially harmful if converted to deoxy-UTP. We also found that the antiretroviral drug azidothymidine (AZT) was an equally good substrate as thymidine and was active against WT as well as metronidazole-resistant G. intestinalis trophozoites. This drug inhibited DNA synthesis in the parasite and efficiently decreased cyst production in vitro, which suggests that it could reduce infectivity. AZT also showed a good effect in G. intestinalis–infected gerbils, reducing both the number of trophozoites in the small intestine and the number of viable cysts in the stool. Taken together, these results suggest that the absolute dependency of the parasite on thymidine kinase for its DNA synthesis can be exploited by AZT, which has promise as a future medication effective against metronidazole-refractory giardiasis. American Society for Biochemistry and Molecular Biology Inc. 2022-06 info:eu-repo/semantics/article info:eu-repo/semantics/closedAccess application/pdf spa http://pa.bibdigital.ucc.edu.ar/3213/1/A_Luj%C3%A1n_Saura_Luj%C3%A1n.pdf Krakovka, Sascha, Ranjbarian, Farahnaz, Luján, Lucas A. ORCID: https://orcid.org/0000-0003-4235-4301 <https://orcid.org/0000-0003-4235-4301>, Saura, Alicia ORCID: https://orcid.org/0000-0003-1537-506X <https://orcid.org/0000-0003-1537-506X>, Larsen, Nicolai B., Jiménez-González, Alejandro ORCID: https://orcid.org/0000-0003-3493-4154 <https://orcid.org/0000-0003-3493-4154>, Reggenti, Anna, Luján, Hugo Daniel ORCID: https://orcid.org/0000-0002-3797-8315 <https://orcid.org/0000-0002-3797-8315>, Svärd, Staffan G. and Hofer, Anders (2022) Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery. Journal of Biological Chemistry, 298 (6). ISSN 0021-9258 https://www.sciencedirect.com/science/article/pii/S0021925822004689?via%3Dihub info:eu-repo/semantics/altIdentifier/doi/https://doi.org/10.1016/j.jbc.2022.102028 |
| institution |
Universidad Católica de Córdoba |
| institution_str |
I-38 |
| repository_str |
R-144 |
| collection |
Producción Académica Universidad Católica de Córdoba (UCCor) |
| language |
Español |
| orig_language_str_mv |
spa |
| topic |
R Medicina (General) RZ Otros sistemas de la medicina |
| spellingShingle |
R Medicina (General) RZ Otros sistemas de la medicina Krakovka, Sascha Ranjbarian, Farahnaz Luján, Lucas A. Saura, Alicia Larsen, Nicolai B. Jiménez-González, Alejandro Reggenti, Anna Luján, Hugo Daniel Svärd, Staffan G. Hofer, Anders Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| topic_facet |
R Medicina (General) RZ Otros sistemas de la medicina |
| description |
Giardiasis is a diarrheal disease caused by the unicellular parasite Giardia intestinalis, for which metronidazole is the main treatment option. The parasite is dependent on exogenous deoxyribonucleosides for DNA replication and thus is also potentially vulnerable to deoxyribonucleoside analogs. Here, we characterized the G. intestinalis thymidine kinase, a divergent member of the thymidine kinase 1 family that consists of two weakly homologous parts within one polypeptide. We found that the recombinantly expressed enzyme is monomeric, with 100-fold higher catalytic efficiency for thymidine compared to its second-best substrate, deoxyuridine, and is furthermore subject to feedback inhibition by dTTP. This efficient substrate discrimination is in line with the lack of thymidylate synthase and dUTPase in the parasite, which makes deoxy-UMP a dead-end product that is potentially harmful if converted to deoxy-UTP. We also found that the antiretroviral drug azidothymidine (AZT) was an equally good substrate as thymidine and was active against WT as well as metronidazole-resistant G. intestinalis trophozoites. This drug inhibited DNA synthesis in the parasite and efficiently decreased cyst production in vitro, which suggests that it could reduce infectivity. AZT also showed a good effect in G. intestinalis–infected gerbils, reducing both the number of trophozoites in the small intestine and the number of viable cysts in the stool. Taken together, these results suggest that the absolute dependency of the parasite on thymidine kinase for its DNA synthesis can be exploited by AZT, which has promise as a future medication effective against metronidazole-refractory giardiasis. |
| format |
Artículo |
| author |
Krakovka, Sascha Ranjbarian, Farahnaz Luján, Lucas A. Saura, Alicia Larsen, Nicolai B. Jiménez-González, Alejandro Reggenti, Anna Luján, Hugo Daniel Svärd, Staffan G. Hofer, Anders |
| author_facet |
Krakovka, Sascha Ranjbarian, Farahnaz Luján, Lucas A. Saura, Alicia Larsen, Nicolai B. Jiménez-González, Alejandro Reggenti, Anna Luján, Hugo Daniel Svärd, Staffan G. Hofer, Anders |
| author_sort |
Krakovka, Sascha |
| title |
Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| title_short |
Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| title_full |
Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| title_fullStr |
Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| title_full_unstemmed |
Giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for DNA synthesis and an exploitable target for drug discovery |
| title_sort |
giardia intestinalis thymidine kinase is a high-affinity enzyme crucial for dna synthesis and an exploitable target for drug discovery |
| publisher |
American Society for Biochemistry and Molecular Biology Inc. |
| publishDate |
2022 |
| url |
http://pa.bibdigital.ucc.edu.ar/3213/1/A_Luj%C3%A1n_Saura_Luj%C3%A1n.pdf |
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