Application of the FBDD technique ¨fragment based drug discovery¨ to the DHFR enzyme of the folate biosynthesis pathway in Mycobacterium tuberculosis

Author(s)

João Augusto Ribeiro

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2018-08-15

Examining board members

Marcio Vinicius Bertacine Dias; Ana Carolina de Mattos Zeri; Elizabeth Bilsland; João Renato Carvalho Muniz; Flavio da Silva Emery

• Advisor: Marcio Vinicius Bertacine Dias

Abstract

Tuberculosis is still ranked among the three most alarming infectious diseases due to its high mortality rate, long treatment period, the prevalence of drug-resistant strains and association with HIV. Integrated private and public sector initiatives are critical for the development of new therapies that attenuates adverse effects related to the current treatment of tuberculosis. For this, a strategy is the development of inhibitors against enzymes of the infectious agent that, even conserved in humans, have peculiarities that could be explored in the search for specificity. The folate biosynthesis pathway has such enzymes, and drugs that inhibit some of them have been used for decades in the treatment of various infections, although there are no effective inhibitors for this pathway in the treatment of tuberculosis. In this work, the technique of fragment-based drug design (FBDD) was applied for the identification of simple molecules with the possibility of being chemically modified to generate inhibitors against dihydrofolate reductase from the folate pathway in Mycobacterium tuberculosis (MtDHFR). Thus, these fragments were submitted to a series of biophysical and crystallographic techniques that allowed their interaction characterization with the target. This characterization was based on the identification of relevant chemical groups present in the fragments for the interaction; on the quantification of affinities; and on the energetic behavior of the interactions. This approach allowed the identification of specific regions of the active site where these interactions could occur and the rational planning of new compounds based on the structure exploring new regions for the gain of affinity. In this way, all initial steps of a typical FBDD campaign were achieved, including the screening and identification of hits, characterization of the interactions and chemical optimization of these initial hits, aiming to obtain leading compounds with the potential to generate new drugs. In addition, together with specialists from Medicinal Chemistry area, we have identified by SAR catalog new compounds analogous to the initially characterized fragments. These compounds had a considerable gain of affinity with the target and could be considered as starting points for obtaining novel lead compounds against M. tuberculosis (AU)

• FAPESP's process: 13/15906-5 - Fragment based drug discovery (FBDD) applied to two enzymes of folate biosynthetic pathway from Mycobacterium tuberculosis
• Grantee: João Augusto Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate