SCIENCE

Robot's in the making.

Fri Feb 07 2025
Chemists took off on a quest. The aim was to change how enzymes work. These enzymes are like tiny machines given sugar as a source of any damage. Dig into enzymes known as pyranose oxidase (POx) and C-glycoside oxidase (CGOx). Part of the oxidoreductase family, these enzymes are the work of FAD. Both POx and CGOs share a similar structure. POx, in its natural form, is active with monosaccharides. Monomeric POxs prefer piles of sugars. This preference is due to the structural shape of POxs . When POx is engineered to be dimeric status, it loses its ability to form monomeric groups. This leaves behind some unwanted qualities of the enzyme. Now consider the reverse of this story. Scientists tried to make monomeric POxs act as dimers. Instead, deletion of the head and arm domains affected the shape of the enzyme. Introducing mutations changed how monosaccharide-binding residues work. The enzymes got less hydrophobic thus affecting their preference to mono and di-saccharides. Catalyst efficiencies for phlorizin are 24*10^6 higher when compared to d-xylose. This difference is astounding. The inability of KaPOx to react with glycosides is likely because the dimerization is a result of steric hindrance. This keeps the active site away from bulky groups thus continuing from its dimeric state. The different structural changes have call to their own challenges. The attempt to engineer ScPOx into a dimeric structure failed at the stage of soluble expression. These exposed hydrophobic patches and aggregation were the real reasons behind this failure. The failure of POXs to graft efficiently with glycosides is due to structural barriers and preference to monosaccharides. Key to it all is that these enzymes are still primitive. They need more critical engineering to make sure they perform better. Chemists now need to look at different angles of this process. Future research might involve more enzymes to figure out this deadlock.