Biochemistry and kinects characterization of BsYmaD protein, a peroxidase of Bacillus subtilis with activity centered on cystein residue

• Grant number: 20/01127-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2020
• End date: November 30, 2021
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Luis Eduardo Soares Netto
• Grantee: Lene Clara de Melo dos Santos
• 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

Reactive oxygen species (ROS) are mainly formed during aerobic metabolism and their production is intensified when cells are under chemical, physical and mechanical stresses, generating molecules such as hydrogen peroxide, hydroxyl radical and superoxide anion. These compounds can cause damage to cellular machinery, such as lipid peroxidation and dismantling of the membrane when there is an oxidative stress condition, which is the situation in which the production of EROs and free radicals supplants their elimination. There are, however, enzymatic (e.g. superoxide dismutase, catalase) and non-enzymatic (e.g. vitamins) systems that perform the detoxification of these molecules. Within the enzyme systems, there is a family of peroxidase proteins called Ohr / OsmC that is able to perform the detoxification of organic hydroperoxides. In this family, proteins have peroxidase activity dependent on thiol compounds. In this group, there is a subfamily called Ohr-like, whose proteins are still poorly studied. Our bioinformatics analyzes identified BsYmaD protein as a member of the Ohr-like subfamily. Other studies have shown that transcription factors such as Zur and Spx, related to zinc and diamide stress, respectively, regulate the expression of the ymaD gene. The surprising fact was that ymaD mutant bacteria (ymaD) was sensitive to the H2O2 challenge, suggesting that BsYmaD would be efficient in detoxifying this hydroperoxide. These observations contrast with the specificity of Ohr / OsmC family proteins for organic peroxides. Therefore, the objective of this project is to characterize the BsYmaD protein biochemically and kinetically, as well as to look for clues regarding its cellular function and physiological reducing system. (AU)