O2-tolerant CO dehydrogenase via tunnel redesign for the removal of CO from industrial flue gas

Ni–Fe carbon monoxide dehydrogenases (CODHs) are nearly diffusion-limited biocatalysts that oxidize CO. Their O2 sensitivity, however, is a major drawback for industrial applications. Here we compare the structures of fast CODH with high sensitivity (ChCODH-II) and slower lower (ChCODH-IV) (Ch, Carboxydothermus hydrogenoformans). Some variants obtained by simple point mutations bottleneck residue (A559) in gas tunnel showed 61–148-fold decreases while maintaining turnover rates. The variant structure A559W obstruction one tunnel, molecular dynamics supported locked position mutated side chain tunnel. was exposed to different mixtures, from synthetic sophisticated real flue steel mill. Its catalytic properties remained unchanged, even at levels, efficiency maintained multiple cycles CO detoxification/regeneration. able rate, but their application. This work shows CODHs can be tailored or cleaning processes engineering selectivity channels.