title: Biochemical and Structural Insights into a Novel Thermostable β-1,3-Galactosidase from Marinomonas sp. BSi20414.
abstract: A novel β-1,3-galactosidase, designated as MaBGA (β-galactosidase fromMarinomonassp. BSi20414), was successfully purified to homogeneity fromMarinomonassp. BSi20414 isolated from Arctic sea ice by ammonium sulfate precipitation and anion exchange chromatography, resulting in an 8.12-fold increase in specific activity and 9.9% recovery in total activity. MaBGA displayed its maximum activity at pH 6.0 and 60 °C, and maintained at least 90% of its initial activity over the pH range of 5.0-8.0 after incubating for 1 h. It also exhibited considerable thermal stability, which retained 76% of its initial activity after incubating at 50 °C for 6 h. In contrast to other β-galactosidases, MaBGA displayed strict substrate specificity, not only for the glycosyl group, but also for the linkage type. To better understand the structure-function relationship, the encoding gene of MaBGA was obtained and subject to bioinformatics analysis. Multiple alignments and phylogenetic analysis revealed that MaBGA belonged to the glycoside hydrolase family 42 and had closer genetic relationships with thermophilic β-galactosidases of extremophiles. With the aid of homology modeling and molecular docking, we proposed a reasonable explanation for the linkage selectivity of MaBGA from a structural perspective. On account of the robust stability and 1,3-linkage selectivity, MaBGA would be a promising candidate in the biosynthesis of galacto-oligosaccharide with β1-3 linkage.
authors.affiliation: SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China. htding@outlook.com.
authors.forename: Haitao
authors.initials: H
authors.lastname: Ding
authors.affiliation: SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China. zengqianmu@126.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China. lilizhou1199@163.com.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhou
authors.affiliation: SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China. yuyong@pric.org.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yu
authors.affiliation: SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China. chenbo@pric.org.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D001110:Arctic Regions; D003001:Cloning, Molecular / Q000379:methods; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D046448:Ice Cover; D053544:Marinomonas / Q000737:chemistry* / Q000235:genetics; D062105:Molecular Docking Simulation / Q000379:methods; D010802:Phylogeny; D016415:Sequence Alignment; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000737:chemistry*
chemical_list: D001616:beta-Galactosidase
keywords: Marinomonas; gene cloning; linkage selectivity; purification; thermostable; β-galactosidase