Functional studies on thioredoxin systems of fungi: characterization of enzymatic specificities

• Grant number: 16/18632-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2016
• End date: September 30, 2017
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Luis Eduardo Soares Netto
• Grantee: Julia Pedroso Reis
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/07937-8 - Redoxome - Redox Processes in Biomedicine, AP.CEPID

Abstract

Disulfide reduction is a central aspect of life. In fact, the production of deoxyribonucleotides, components of DNA, involves thiol-disulfide exchange reactions. The thioredoxin system is composed of two proteins (Thioredoxin (Trx), and Thioredoxin Reductase (TrxR)), and NADPH and plays a central role in desoxyribunucleotides synthesis, besides acting as a reductant of antioxidant proteins such as Peroxiredoxins and Methionine Sulfoxide Reductase, among other systems. Our research group, characterized cytosolic thioredoxin system from Saccharomyces cerevisiae, showing ScTrxR1 is able to reduce yeast Trxs with high efficiency (kcat / KM ~ 10^7 M^-1 s^-1), but did not observe reaction in significant rates with Trxs from Escherichia coli and Homo Sapiens (Oliveira et .al., 2010). In this research project, we intend to advance these studies, characterizing the mitochondrial thioredoxin system from Saccharomyces cerevisiae (composed of ScTrxR2 ScTrx3 + NADPH +) and also the thioredoxin system from Aspergillus fumigatus (composed of AfTrxR1 AfTrx1-4 + NADPH +), aiming to characterize specificities of TrxRs towards Trx from various organisms using enzymatic assays and structural approaches.