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Mass spectrometry characterization for chemoenzymatic glycoprotein synthesis
Author(s) -
Schiel John E.,
Lowenthal Mark S.,
Phinney Karen W.
Publication year - 2011
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1934
Subject(s) - chemistry , glycan , glycosylation , mass spectrometry , oxazoline , glycoprotein , combinatorial chemistry , rnase p , ribonuclease , stereochemistry , biochemistry , chromatography , catalysis , rna , gene
The current project describes the chemoenzymatic modification of bovine ribonuclease B (RNase B) to contain a single glycosylation site with a known glycan. A reactive disaccharide oxazoline derivative was synthesized and stereospecifically added to deglycosylated RNase B through endo‐β‐ N ‐acetylglucosaminidase M catalyzed chemoenzymatic transglycosylation. Oxazoline formation conditions were optimized using mass spectrometry, and the product verified based on its collision‐induced dissociation (CID) mass spectrum. Enzymatic removal of native glycans as well as formation of the desired homogeneous product was also monitored using mass spectrometry. LC‐MS n using four sequential rounds of CID was used to verify that the original glycosylation site had been reorganized to contain the new glycan. The techniques described herein are not limited to this analyte or glycan and should be amenable to the synthesis of numerous homogeneous glycoconjugates with judicious choice of enzyme/substrate combinations. The combined use of chemoenzymatic synthesis and mass spectrometry‐based characterization shows promise for the development of homogeneous glycoprotein reference materials. A well‐defined glycoprotein standard containing a single glycan of known composition, linkage and stereochemistry would be of great value for the comparison and evaluation of glycoprotein analysis techniques. Copyright © 2011 John Wiley & Sons, Ltd.