Structural and Functional Characterization of cGMP-Dependent Protein Kinase (PKG) Mutants of Plasmodium falciparum Resistant to Inhibitors

• Grant number: 25/11960-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Rafael Victorio Carvalho Guido
• Grantee: Raquel Barbosa Lélis
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 24/04805-8 - Integrated investigation of inhibitors active on infectious diseases: insights into molecular and cellular mechanisms of function, AP.TEM

Abstract

Malaria is a severe infectious disease caused by the Plasmodium parasite, posing one of the greatest challenges to global public health. Despite significant advances in combating the disease, the growing resistance to antimalarial therapies, particularly those involving artemisinin-based combination therapies (ACTs), threatens to undermine the progress achieved. In this context, the cGMP-dependent protein kinase of P. falciparum (PfPKG) has emerged as a promising target for the development of new drugs. PfPKG plays a crucial role in the parasite's life cycle and exhibits structural differences from human PKGs, enabling the creation of selective inhibitors. This project focuses on investigating specific mutations in PfPKG that confer resistance to these inhibitors. Three variants of PfPKG (e.g., I602M, T618I, and T618Q) known to modify the interaction of compounds with the enzyme's active site were selected for biochemical and structural studies. The genes encoding these mutated proteins were obtained through site-directed mutagenesis techniques and cloned into expression vectors for production in insect cells. The mutated PfPKGs will be purified and analyzed using enzymatic kinetics and X-ray crystallography methods. Understanding the structural and functional impacts of these mutations will help assess the efficacy of inhibitors and provide the molecular and biochemical determinants for the development of more effective compounds against resistant strains of P. falciparum. This research aims to contribute to innovative antimalarial strategies, with a focus on advancing effective therapies to combat malaria more effectively.