CHARACTERIZATION OF G-QUADRUPLEX STRUCTURES IN THE MAYARO VIRUS GENOME AND THEIR INTERACTION WITH PORPHYRIN TMPyP4

Mayaro virus (MAYV) is an emerging arbovirus that poses a threat to public health and is often underreported. Treatment of MAYV infection is currently limited to symptomatic management. In this context, G-quadruplex (G4) structures have emerged as promising molecular targets for antiviral development. Although these structures have already been studied in other viruses and arboviruses, knowledge of their presence in the MAYV genome remains limited. Among the ligands described in the literature, the porphyrin TMPyP4 stands out for its significant affinity for G-quadruplex structures and for demonstrated antiviral activity against various viruses. In view of this scenario, the main aim of this study is to characterize the formation and stability of G-quadruplex structures in three previously proposed RNA fragments under salt-free buffer conditions and the presence of KCl and NaCl, and to determine interaction parameters, such as the dissociation constant and binding stoichiometry, between these G4 structures and porphyrin TMPyP4. The results obtained so far indicate, by circular dichroism (CD) analysis, that one of the proposed sequences exhibits a structural topological profile characteristic of G4 structures, adopting an antiparallel and hybrid conformation under KCl and NaCl conditions, respectively. In addition, the thermal denaturation profiles of the antiparallel and hybrid conformations showed cooperative behavior, with melting temperatures of ~57 and ~43 °C, respectively. The interaction of the G4 structures in antiparallel and hybrid conformations with the porphyrin TMPyP4 revealed changes in the CD profiles, including increased thermal stability and decreased cooperativity during thermal unfolding, suggesting significant alterations in the RNA secondary structure. Therefore, the next steps will involve analyzing the interaction between porphyrin and G4 structures using fluorescence and UV-Vis spectroscopy. Thus, this work can advance understanding of MAYV molecular mechanisms, particularly the formation of G-quadruplex structures in its genome, potentially opening new avenues for developing innovative therapeutic strategies by exploring G4 structures as promising antiviral targets.