A switch in a substrate tunnel for directing regioselectivity of nitrile hydratases towards α,ω-dinitriles
Zhongyi Cheng, Wenjing Cui, Zhongmei Liu, Li Zhou, Min Wang, Michihiko Kobayashi and Zhemin Zhou
Zhongyi Cheng, Wenjing Cui, Zhongmei Liu, Li Zhou, Min Wang, Michihiko Kobayashi and Zhemin Zhou
The β37 residue of nitrile hydratase (NHase) from Pseudomonas putida and NHase from Comamonas testosteroni played a critical role in directing enzyme regioselectivity. Amino acid substitution in this site modulated or even inverted enzyme regioselectivity towards aliphatic α,ω-dinitriles.
Cartoon model of the substrate access tunnel of (a) wild-type PpNHase and its (b) L37F and (c) L37Y variants, and (d) wild-type CtNHase and its (e) F37L and (f) F37P variants. The protein structures of PpNHase and CtNHase are shown as the grey cartoon. The β37 residues of NHases are shown as blue sticks. The purple balls and sticks represent the catalytic site of NHase. The bottleneck-forming amino acids are shown as red sticks. The tunnels are shown as green spheres, and the tunnel bottlenecks are coloured in yellow. All the figures share the same size proportion.
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