75598-07-1Relevant academic research and scientific papers
Novel substrate specificities of two lacto-N-biosidases towards β-linked galacto-N-biose-containing oligosaccharides of globo H, Gb5, and GA1
Gotoh, Aina,Katoh, Toshihiko,Sugiyama, Yuta,Kurihara, Shin,Honda, Yuji,Sakurama, Haruko,Kambe, Taiho,Ashida, Hisashi,Kitaoka, Motomitsu,Yamamoto, Kenji,Katayama, Takane
, p. 18 - 24 (2015/04/14)
We describe the novel substrate specificities of two independently evolved lacto-N-biosidases (LnbX and LnbB) towards the sugar chains of globo- and ganglio-series glycosphingolipids. LnbX, a non-classified member of the glycoside hydrolase family, isolated from Bifidobacterium longum subsp. longum, was shown to liberate galacto-N-biose (GNB: Galβ1-3GalNAc) and 2′-fucosyl GNB (a type-4 trisaccharide) from Gb5 pentasaccharide and globo H hexasaccharide, respectively. LnbB, a member of the glycoside hydrolase family 20 isolated from Bifidobacterium bifidum, was shown to release GNB from Gb5 and GA1 oligosaccharides. This is the first report describing enzymatic release of β-linked GNB from natural substrates. These unique activities may play a role in modulating the microbial composition in the gut ecosystem, and may serve as new tools for elucidating the functions of sugar chains of glycosphingolipids.
Highly efficient enzymatic synthesis of Galβ-(1→3)-GalNAc and Galβ-(1→3)-GlcNAc in ionic liquids
Bayón, Carlos,Cortés, álvaro,Berenguer, José,Hernáiz, María J.
, p. 4973 - 4978 (2013/06/27)
Ionic liquids (ILs) have emerged as an alternative to conventional organic media due to their high thermal and chemical stability, negligible vapour pressure, non-flammability and easy recycling. In this context, this work assesses the catalytic activity of a β-galactosidase from Bacillus circulans ATCC 31382 (β-Gal-3-NTag) in the synthesis of β-(1→3)-galactosides using different ILs. A noticeably increase in activity, retaining total regioselectivity was found in the synthetic behaviour of B. circulans β-galactosidase in ILs as co-solvents and using a 1:5 molar ratio of donor (pNP-β-Gal):acceptor (GlcNAc or GalNac). Yields up to 97% of β-(1→3) with different ILs were found. These reactions take place without noticeable hydrolytic activity and with total regioselectivity, representing a considerable improvement over the use of aqueous buffer or conventional organic solvents. Furthermore, reaction scaling up and IL recovery and recycling are feasible without losing catalytic action. Molecular modelling studies performed predict a three-dimensional interaction at the active centre between the acceptor and the water-IL mixture, which could explain the results obtained.
Highly efficient and regioselective enzymatic synthesis of β-(1→3) galactosides in biosolvents
Bayon, Carlos,Cortes, Alvaro,Aires-Trapote, Antonio,Civera, Concepcion,Hernaiz, Maria Jose
, p. 12155 - 12163 (2013/09/02)
A green synthesis for β-(1→3) galactosyldisaccharides that combines the use of a biodegradable biocatalyst, aqueous solutions, and solvent recycling (renewable and derived from biomass) has been developed. The use of biomass-derived solvents allows good catalytic activity in the synthesis of Gal-β-d-(1→3)GlcNAc and Gal-β-d-(1→)3GalNAc (99% and 95% yields respectively) with β-Gal-3-NTag β-galactosidase, preventing hydrolytic activity and with full regioselectivity. This represents a considerable improvement over the use of an aqueous buffer or conventional organic solvents. Furthermore, reaction scaling up and biosolvent recycling are feasible without losing catalytic action. In order to understand the role of these green solvents in the enzyme's synthetic behaviour, different structural studies were performed (fluorescence and molecular modelling) in the presence of some selected biosolvents to conclude that the presence of green biosolvents in the reaction media modifies the enzyme's tertiary structure allowing better substrate disposition in the active site, most probably due to solvation effects, explaining the behaviour observed. The Royal Society of Chemistry 2013.
Crystal structures of a glycoside hydrolase family 20 lacto-N-biosidase from Bifidobacterium bifidum
Ito, Tasuku,Katayama, Takane,Hattie, Mitchell,Sakurama, Haruko,Wada, Jun,Suzuki, Ryuichiro,Ashida, Hisashi,Wakagi, Takayoshi,Yamamoto, Kenji,Stubbs, Keith A.,Fushinobu, Shinya
, p. 11795 - 11806 (2013/06/26)
Human milk oligosaccharides contain a large variety of oligosaccharides, of which lacto-N-biose I (Gal-β 1, 3-GlcNAc; LNB) predominates as a major core structure. A unique metabolic pathway specific for LNB has recently been identified in the human commensal bifidobacteria. Several strains of infant gut-associated bifidobacteria possess lacto-N-biosidase, a membrane-anchored extracellular enzyme, that liberates LNB from the nonreducing end of human milk oligosaccharides and plays a key role in the metabolic pathway of these compounds. Lacto-N-biosidase belongs to the glycoside hydrolase family 20, and its reaction proceeds via a substrate-assisted catalytic mechanism. Several crystal structures of GH20 β-N-acetylhexosaminidases, which release monosaccharide GlcNAc from its substrate, have been determined, but to date, a structure of lacto-N-biosidase is unknown. Here, we have determined the first three-dimensional structures of lacto-N-biosidase from Bifidobacterium bifidum JCM1254 in complex with LNB and LNB-thiazoline (Gal-β1, 3-GlcNAc-thiazoline) at 1.8-A resolution. Lacto-N-biosidase consists of three domains, and the C-terminal domain has a unique β-trefoil-like fold. Compared with other β-N-acetyl-hexosaminidases, lacto-N-biosidase has a wide substrate-binding pocket with a - 2 subsite specific for β-1, 3-linked Gal, and the residues responsible for Gal recognition were identified. The bound ligands are recognized by extensive hydrogen bonds at all of their hydroxyls consistent with the enzyme's strict substrate specificity for the LNB moiety. The GlcNAc sugar ring of LNB is in a distorted conformation near 4E, whereas that of LNB-thiazoline is in a 4C1 conformation. A possible conformational pathway for the lacto-N-biosidase reaction is discussed.
