THE PUZZLING ARSENITE OXIDASE REACTION MECHANISM: PUTTING THE PIECES TOGETHER

Arsenic water contamination is a worrying environmental and social problem, that affects more than 200 million people worldwide, with incidence on all continents, and it will only be amplified in the next years due to growing populations and increasing water scarcity. The current solutions to detect and remove this toxic metalloid are expensive, time-consuming, based on harmful chemicals and are not yet available to be readily used on-site.

In this work, we studied the biological oxidation of AsIII into AsV via arsenite oxidase from a structural and functional point of view for future applications in sensing and bioremediation. Using several biophysical and structural techniques, such as X-ray crystallography and UV-visible spectroscopy, we obtained the 3D structure of reaction intermediates, highlighting the atomic details used in catalysis. In addition, NMR, bioinformatics and microscale thermophoresis allowed us to quantify the affinity of the interaction between the enzyme and the physiological electron acceptors, as well as to unveil the molecular determinants of the electron transfer

pathway.