Biochemical characterization and biocatalytic application of a novel d-tagatose 3-epimerase from Sinorhizobium sp. Issue 6 (22nd January 2019)

• Record Type: Journal Article
• Authors: Zhu, Zhangliang; Li, Chao; Liu, Xin; Gao, Dengke; Wang, Xueyu; Tanokura, Masaru; Qin, Hui-Min; Lu, Fuping
• Is Part Of: RSC advances. Volume 9:Issue 6(2019)
• Page Start: 2919
• Page End: 2927
• Publication Date: 2019-01-22
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra10029b
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Sinorhizobium sp.d -tagatose 3-epimerase (sDTE) catalyzes the conversion ofd -tagatose tod -sorbose. Abstract : Sinorhizobium sp.d -tagatose 3-epimerase (sDTE) catalyzes the conversion ofd -tagatose tod -sorbose. It also recognizesd -fructose as a substrate ford -allulose production. The optimal temperature and pH of the purified sDTE was 50 °C and 8.0, respectively. Based on the sDTE homologous model, Glu154, Asp187, Gln213, and Glu248, form a hydrogen bond network with the active-site Mn 2+ and constitute the catalytic tetrad. The amino acid residues around O-1, -2, and -3 atoms of the substrates (d -tagatose/d -fructose) are strictly conserved and thus likely regulate the catalytic reaction. However, the residues at O-4, -5, and -6, being responsible for the substrate-binding, are different. In particular, Arg65 and Met9 were found to form a unique interaction with O-4 ofd -fructose andd -tagatose. The whole cells with recombinant sDTE showed a higher bioconversion rate of 42.5% in a fed-batch bioconversion usingd -fructose as a substrate, corresponding to a production of 476 g L −1 d -allulose. These results suggest that sDTE is a potential industrial biocatalyst for the production ofd -allulose in fed-batch mode.