Crystal Structure of <scp>l</scp>-2,4-Diketo-3-deoxyrhamnonate Hydrolase Involved in the Nonphosphorylated <scp>l</scp>-Rhamnose Pathway from Bacteria

2,4-Diketo-3-deoxy-l-rhamnonate (L-DKDR) hydrolase (LRA6) catalyzes the hydrolysis reaction of L-DKDR to pyruvate and l-lactate in the nonphosphorylated l-rhamnose pathway from bacteria and belongs to the fumarylacetoacetate hydrolase (FAH) superfamily. Most of the members of the FAH superfamily are involved in the microbial degradation of aromatic substances and share low sequence similarities with LRA6, by which the underlying catalytic mechanism remains unknown at the atomic level. We herein elucidated for the first time the crystal structures of LRA6 from