title: Chemo-enzymatic synthesis of 4-methylumbelliferyl beta-(1-->4)-D-xylooligosides: new substrates for beta-D-xylanase assays.
abstract: Transglycosylation catalyzed by a beta-D-xylosidase from Aspergillus sp. was used to synthesize a set of 4-methylumbelliferyl (MU) beta-1-->4-D-xylooligosides having the common structure [beta-D-Xyl-(1-->4)]2-5-beta-D-Xyl-MU. MU xylobioside synthesized chemically by the condensation of protected MU beta-D-xylopyranoside with ethyl 2,3,4-tri-O-acetyl-1-thio-beta-D-xylopyranoside was used as a substrate for transglycosylation with the beta-D-xylosidase from Aspergillus sp. to produce higher MU xylooligosides. The structures of oligosaccharides obtained were established by 1H and 13C NMR spectroscopy and electrospray tandem mass spectrometry. MU beta-D-xylooligosides synthesized were tested as fluorogenic substrates for the GH-10 family beta-D-xylanase from Aspergillus orizae and the GH-11 family beta-D-xylanase I from Trichoderma reesei. Both xylanases released the aglycone from MU xylobioside and the corresponding trioside. With substrates having d.p. 4 and 5, the enzymes manifested endolytic activities, splitting off MU, MUX, and MUX2 primarily.
authors.affiliation: Petersburg Nuclear Physics Institute, Russian Academy of Science, Molecular and Radiation Biology Division, Gatchina, 188300, Russia.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Eneyskaya
authors.forename: Dina R
authors.initials: DR
authors.lastname: Ivanen
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Shabalin
authors.forename: Anna A
authors.initials: AA
authors.lastname: Kulminskaya
authors.forename: Leon V
authors.initials: LV
authors.lastname: Backinowsky
authors.forename: Harry
authors.initials: H
authors.lastname: Brumer Iii
authors.forename: Kirill N
authors.initials: KN
authors.lastname: Neustroev
mesh_terms: D001230:Aspergillus / Q000201:enzymology; D002240:Carbohydrate Sequence; D002247:Carbon Isotopes; D002384:Catalysis; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D011522:Protons; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014242:Trichoderma / Q000201:enzymology; D014995:Xylosidases / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D009844:Oligosaccharides; D011522:Protons; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase