title: Chemoenzymatic synthesis and lectin recognition of a selectively fluorinated glycoprotein.
abstract: A chemoenzymatic glycosylation remodeling method for the synthesis of selectively fluorinated glycoproteins is described. The method consists of chemical synthesis of a fluoroglycan oxazoline and its use as donor substrate for endoglycosidase (ENGase)-catalyzed transglycosylation to a GlcNAc-protein to form a homogeneous fluoroglycoprotein. The approach was exemplified by the synthesis of fluorinated glycoforms of ribonuclease B (RNase B). An interesting finding was that fluorination at the C-6 of the 6-branched mannose moiety in the Man3GlcNAc core resulted in significantly enhanced reactivity of the substrate in enzymatic transglycosylation. A structural analysis suggests that the enhancement in reactivity may come from favorable hydrophobic interactions between the fluorine and a tyrosine residue in the catalytic site of the enzyme (Endo-A). SPR analysis of the binding of the fluorinated glycoproteins with lectin concanavalin A (con A) revealed the importance of the 6-hydroxyl group on the α-1,6-branched mannose moiety in con A recognition. The present study establishes a facile method for preparation of selectively fluorinated glycoproteins that can serve as valuable probes for elucidating specific carbohydrate-protein interactions.
authors.affiliation: Institute of Human Virology and Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA.
authors.forename: Jared
authors.initials: J
authors.lastname: Orwenyo
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Lai-Xi
authors.initials: LX
authors.lastname: Wang
mesh_terms: D055162:Biocatalysis; D005461:Fluorine / Q000737:chemistry*; D006023:Glycoproteins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D054879:Halogenation; D057927:Hydrophobic and Hydrophilic Interactions; D037102:Lectins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D010080:Oxazoles / Q000737:chemistry / Q000378:metabolism; D012260:Ribonucleases / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D037102:Lectins; D010080:Oxazoles; D005461:Fluorine; D012260:Ribonucleases; C029600:ribonuclease B; D006026:Glycoside Hydrolases
keywords: Endoglycosidase; Fluorine; Fluorosugar; Glycoprotein; Lectin; Transglycosylation