Crystal Structure of Cobalt-Containing Nitrile Hydratase

Abstract

The crystal structure of cobalt-containing nitrile hydratase from Pseudonocardia thermophila JCM 3095 at 1.8 Å resolution revealed the structure of the noncorrin cobalt at the catalytic center. Two cysteine residues (αCys111 and αCys113) coordinated to the cobalt were posttranslationally modified to cysteine-sulfinic acid and to cysteine-sulfenic acid, respectively, like in iron-containing nitrile hydratase. A tryptophan residue (βTrp72), which may be involved in substrate binding, replaced the tyrosine residue of iron-containing nitrile hydratase. The difference seems to be responsible for the preference for aromatic nitriles rather than aliphatic ones of cobalt-containing nitrile hydratase.