Biological function of pH sensitivity in firefly luciferases: effects of pH, temperature and [phosphate] variations in modulating activity and bioluminescence spectra in fireflies

• Grant number: 24/18826-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Biological Sciences - Biophysics - Radiology and Photobiology
• Principal Investigator: Vadim Viviani
• Grantee: Gabriel Fracacio Andrade
• Host Institution: Centro de Ciências e Tecnologias para a Sustentabilidade (CCTS). Universidade Federal de São Carlos (UFSCAR). Sorocaba , SP, Brazil

Abstract

Firefly luciferases are sensitive to pH, temperature and heavy metals, ranging from green to red. In recent years, it has been demonstrated that this sensitivity can be used analytically to determine intracellular pH and in sensors and assays for heavy metals such as mercury and cadmium. However, it is still unknown whether this enzymatic sensitivity actually has some biological function in fireflies, as it changes the emission spectrum, or whether it is merely a side effect of the more flexible structure of these luciferases. Therefore, in this project, we aim to investigate whether, during the bioluminescent reaction, changes in pH and bioluminescence spectra occur in weakly buffered solutions that simulate photocytes, as well as the effects on the spectra of increased phosphate concentration resulting from ATP hydrolysis in these solutions. We will also investigate how much temperature affects the in vivo bioluminescence spectra of Macrolampis sp2 fireflies to see if changes in environmental temperature affect the spectra, as suggested. Finally, we plan to contribute to the understanding of the structural origin of pH sensitivity in these luciferases.