Download MendeleyCharacterization 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.(2026) Biosci Biotechnol Biochem 90: 746-754
- PubMed: 41854348 Search on PubMed
- DOI: https://doi.org/10.1093/bbb/zbag041
- Primary Citation Related Structures:
9W6Y, 9W7A - PubMed Abstract:
The 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.
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
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