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| Author(s): |
Olívia Teixeira
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2024-02-02 |
| Examining board members: |
Maria Cristina Nonato;
Marcio Vinícius Bertacine Dias;
Richard John Ward
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| Advisor: | Maria Cristina Nonato |
| Abstract | |
Tuberculosis (TB) is a leading cause of death worldwide. TB represents a serious public health threat, and it is characterized by high transmission rates, prevalence in impoverished regions, and high co-infection rates with HIV. Moreover, the serious side effects of long-term treatment that decrease patient adherence, and the emergence of multi-resistant strains of Mycobacterium tuberculosis, the causing agent of TBs, pose several challenges for its eradication. The search for a new TB treatment is necessary and urgent. Dihydroorotate dehydrogenase (DHODH) is responsible for the stereospecific oxidation of (S)-dihydroorotate (DHO) to orotate during the fourth and only redox step of the de novo pyrimidine nucleotide biosynthetic pathway. DHODH has been considered an attractive target against infectious diseases. As a first step towards exploiting DHODH as a drug target against TB, we performed a full kinetic characterization of both bacterial MtDHODH and its human ortholog (HsDHDOH) using both substrates coenzyme Q0 (Q0) and vitamin K3 (K3). MtDHODH follows a ping-pong mechanism of catalysis and shares similar catalytic parameters with the human enzyme. Serendipitously, Q0 was found to inhibit MtDHODH (KI (Q0) = 138 ± 31 µM). To the best of our knowledge, Q0 is the first non-orotate-like dihydroorotate-competitive inhibitor for class 2 DHODHs ever described Molecular dynamics simulations along with in silico solvent mapping, carried out based on a three-dimensional model constructed through homology modeling and validated by artificial intelligence methods implemented in Alphafold, have allowed us to assess the protein\'s flexibility and relate it to potential modulation of its activity by small ligand molecules at different sites on the protein. It was also possible to obtain the crystallographic structure of MtDHODH at a resolution of 2.5 Å, which not only provides important structural information but also validates the previously generated model. Together, our results provide the starting point for designing a new generation of potent and selective inhibitors against MtDHODH. (AU) | |
| FAPESP's process: | 20/16316-0 - Search for potent and selective inhibitors to Mycobacterium tuberculosis dihydroorotate dehydrogenase (MtDHODH) |
| Grantee: | Olívia Teixeira |
| Support Opportunities: | Scholarships in Brazil - Master |