Mechanistic study of luciferin-luciferase interaction in fungi

• Grant number: 18/06686-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2018
• End date: January 31, 2020
• Field of knowledge: Biological Sciences - Biophysics - Radiology and Photobiology
• Principal Investigator: Cassius Vinicius Stevani
• Grantee: Marco Totini Tanezi
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The present scientific initiation project aims to study the chemical mechanism of the reaction of fungal luciferin (3-hydroxyphispidine) with the recombinant luciferase of the fungus Neonothopanus nambi. Fungal luciferase, as a promiscuous enzyme, also accepts other substrates, leading to the emission of light. It is intended to perform kinetic studies with each of the thirteen luciferin derivatives available in the laboratory and to evaluate possible correlations between the observed light decay rate constant (kobs) with the oxidation potential of luciferins (Eox) and Hammett's Ã, for nine of the thirteen available derivatives. Fluorescence quantum yield values (¦FL) will also be determined for natural and synthetic oxyluciferin. Finally, free-energy relationships will be investigated between lnkobs vs. Eox, lnkobs vs. Ã and ln¦FL vs. the polarity of the solvent. (AU)