24960-16-5Relevant articles and documents
Crystal structures and functional studies clarify substrate selectivity and catalytic residues for the unique orphan enzyme N-acetyl-D-mannosamine dehydrogenase
Sola-Carvajal, Agustin,Gil-Ortiz, Fernando,Garcia-Carmona, Francisco,Rubio, Vicente,Sanchez-Ferrer, Alvaro
, p. 499 - 511 (2014)
NAMDH (N-acetyl-D-mannosamine dehydrogenase), from the soil bacteroidete Flavobacterium sp. 141-8, catalyses a rare NAD+ -dependent oxidation of ManNAc (N-acetyl-Dmannosamine) into N-acetylmannosamino-lactone, which spontaneously hydrolyses into N-acetylmannosaminic acid. NAMDH belongs to the SDR (short-chain dehydrogenase/reductase) superfamily and is the only NAMDH characterized to date. Thorough functional, stability, site-directed mutagenesis and crystallographic studies have been carried out to understand better the structural and biochemical aspects of this unique enzyme. NAMDH exhibited a remarkable alkaline pH optimum (pH 9.4) with a high thermal stability in glycine buffer (Tm =64°C) and a strict selectivity towards ManNAc and NAD+ . Crystal structures of ligand-free and ManNAc- and NAD + -bound enzyme forms revealed a compact homotetramer having point 222 symmetry, formed by subunits presenting the characteristic SDR α3β7α3 sandwich fold. A highly developed C-terminal tail used as a latch connecting nearby subunits stabilizes the tetramer. A dense network of polar interactions with the substrate including the encasement of its acetamido group in a specific binding pocket and the hydrogen binding of the sugar 4OH atom ensure specificity for ManNAc. The NAMDH-substrate complexes and site-directed mutagenesis studies identify the catalytic tetrad and provide useful traits for identifying new NAMDH sequences.
Chemo-enzymatic approach to access diastereopure α-substituted GlcNAc derivatives
Wang, Su-Yan,Laborda, Pedro,Lu, Ai-Min,Wang, Meng,Duan, Xu-Chu,Liu, Li,Voglmeir, Josef
, p. 423 - 434 (2017/08/23)
The formation of diastereopure α-substituted GlcNAc derivatives in a simple and straightforward way is a challenging task. Herein, we report the chemical synthesis of diastereomeric α/β-substituted GlcNAc derivatives under non-anhydrous atmosphere using u