A novel disaccharide substrate having 1,2-oxazoline moiety for detection of transglycosylating activity of endoglycosidases.
A disaccharide substrate of Manbeta1-4GlcNAc-oxazoline 2 was designed and synthesized as a novel probe for detection of the transglycosylating activity of endoglycosidases. A regio- and stereoselective transglycosylation reaction of 2 to GlcNAcbeta1-O-pNP or Dns-Asn(GlcNAc)-OH catalyzed by endo-beta-N-acetylglucosaminidase from Mucor hiemalis (Endo-M) and endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (Endo-A) has been demonstrated for the first time, resulting in the core trisaccharide derivative Manbeta1-4GlcNAcbeta1-4GlcNAcbeta1-O-pNP 8 (or -(Dns)Asn-OH). Interestingly, the transglycosylation proceeds irreversibly; the resulting trisaccharide 8 was not hydrolyzed by Endo-M and Endo-A. Based on these results, a new mechanism including an oxazolinium ion intermediate has been proposed for the endoglycosidase-catalyzed hydrolysis or transglycosylation.
Fujita
M
M
Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan.
Shoda
S
S
Haneda
K
K
Inazu
T
T
Takegawa
K
K
Yamamoto
K
K
D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis*; D006026:Glycoside Hydrolases / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000737:chemistry; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry; D013379:Substrate Specificity; D014166:Transferases / Q000737:chemistry; D014312:Trisaccharides / Q000138:chemical synthesis
D004187:Disaccharides; D009097:Multienzyme Complexes; D014312:Trisaccharides; C023176:transglycosidase enzyme system; D014166:Transferases; D006026:Glycoside Hydrolases; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase