Structure of an Escherichia coli N-acetyl-D-neuraminic acid lyase mutant, E192N, in complex with pyruvate at 1.45 Å resolution

The structure of a mutant variant of Escherichia coli N-acetyl-D-neuraminic acid lyase (NAL), E192N, in complex with pyruvate has been determined in a new crystal form. It crystallized in space group P2₁2₁2₁, with unit-cell parameters a = 78.3, b = 108.5, c = 148.3 Å. Pyruvate has been trapped in the active site as a Schiff base with the catalytic lysine (Lys165) without the need for reduction. Unlike the previously published crystallization conditions for the wild-type enzyme, in which a mother-liquor-derived sulfate ion is strongly bound in the catalytic pocket, the low-salt conditions described here will facilitate the determination of further E. coli NAL structures in complex with other active-site ligands.