Structural details of the enzymatic catalysis of carbonic anhydrase II via a mutation of valine to isoleucine

Kim and co-workers [IUCrJ (2020). 7, 985–994] advance our understanding of the catalytic mechanism of carbonic anhydrase II by studying a mutant V143I where the change (of one hydrophobic amino acid to another that differs by a single CH2 group) is probably the smallest alteration that can be introduced into a protein. The study was performed at high pressure in a CO2 atmosphere to visualize the bound substrate; it showed the behavior of the entrance conduit waters and the substrate alteration due to the mutation.