Structural highlights
Publication Abstract from PubMedThe crystal structure of l-galactose dehydrogenase (LGDH) with l-glucose dehydrogenase activity from Luteolibacter sp. strain LG18 (Lu-LGDH) was determined in complex with l-galactose or l-glucose and NADP(+). This structural analysis identified key residues involved in substrate binding, and alanine-substituted mutants demonstrated the roles of these residues, including Tyr56, acting as potential general base within the catalytic tetrad. Unlike plant enzymes that show a preference for NAD(+), Lu-LGDH exhibits a marked preference for NADP(+) as a cofactor. This preference was attributed to the interaction of the phosphate group with Arg28, Thr269, and Asn274. The binding mode of l-glucose was similar to that of l-galactose. The C4 hydroxyl group (the structural difference between these pyranoses) was not used for substrate binding, which explains the dual activity of the enzyme. Furthermore, among the substrate-binding residues that were mutated, Arg308, which is not conserved among LGDHs, was crucial for the enzymatic activity. Characterization of bacterial l-galactose dehydrogenase with l-glucose dehydrogenase activity from Luteolibacter sp. strain LG18.,Koubara K, Kim M, Takenoya M, Nakanishi A, Suzuki M, Azuma S, Ito S, Sasaki Y, Nakamura A, Yajima S Biosci Biotechnol Biochem. 2026 Mar 19:zbag041. doi: 10.1093/bbb/zbag041. PMID:41854348[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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