A Bacterial Myeloperoxidase with Antimicrobial Properties

Abstract

The four mammalian peroxidases (myeloperoxidase, eosinophilperoxidase, lactoperoxidase, and thyroid peroxidase) are widely studied in the literature. They catalyze the formation of antimicrobial compounds and participate in innate immunity. Owing to their properties, they are used in many biomedical, biotechnological, and agro-food applications. We decided to look for an enzyme that is easiest to produce and much more stable at 37 °C than mammalian peroxidases. To address this question, a peroxidase from Rhodopirellula baltica, identified by bioinformatics tools, was fully characterized in this study. In particular, a production and purification protocol including the study of heme reconstitution was developed. Several activity tests were also performed to validate the hypothesis that this peroxidase is a new homolog of mammalian myeloperoxidase. It has the same substrate specificities as the human one and accepts I−, SCN−, Br−, and Cl− as (pseudo-) halides. It also exhibits other auxiliary activities such as catalase and classical peroxidase activities, and it is very stable at 37 °C. Finally, this bacterial myeloperoxidase can kill the Escherichia coli strain ATCC25922, which is usually used to perform antibiograms.

Does Acinetobacter calcoaceticus glucose dehydrogenase produce self-damaging H2O2?

“…The production of hydrogen peroxide (H 2 O 2 ) by sGDH wild-type, Y343F or D143E/Y343F mutants was determined by using Rb MPO [ 54 ] and a fluorescent probe on a SpectraMax® iD3 Multi-Mode Microplate Reader (Molecular Devices). Measurements were performed in Greiner 384-well clear-bottom (flat-bottom) plates with a reaction volume of 20 µl.…”