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Protein‐induced conformational change in glycans decreases the resolution of glycoproteins in hydrophilic interaction liquid chromatography
Author(s) -
Bupp Charles R.,
Schwartz Cameron,
Wei Bingchuan,
Wirth Mary J.
Publication year - 2021
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.202001242
Subject(s) - glycan , glycoprotein , chemistry , selectivity , chromatography , van deemter equation , hydrogen bond , hydrophilic interaction chromatography , steric effects , resolution (logic) , molecule , high performance liquid chromatography , biochemistry , organic chemistry , artificial intelligence , computer science , catalysis
An understanding of why hydrophilic interaction liquid chromatography gives a higher resolution for glycans than for glycoproteins would facilitate column improvements. Separations of the glycoforms of ribonuclease B compared to its released glycans were studied using a commercial hydrophilic interaction liquid chromatography column. The findings were used to devise a new hydrophilic interaction liquid chromatography column. For the commercial column, chromatograms and van Deemter plots showed that selectivity and efficiency are comparable factors in the higher resolution of the released glycans. The higher selectivity for the released glycans was associated with more water molecules displaced per added mannose. To investigate why, three‐dimensional structures of the glycoprotein and the glycan were computed under chromatographic conditions. These showed that hydrogen bonding within the free glycan makes its topology more planar, which would increase contact with the bonded phase. The protein sterically blocks the hydrogen bonding. The more globular‐shaped glycan of the glycoprotein suggests that a thicker bonded phase might improve selectivity. This was tested by making a column with a copolymer bonded phase. The results confirmed that selectivity is increased. The findings are possibly broadly relevant to glycoprotein analysis since the structural motif involved in internal hydrogen bonding is common to N‐linked glycans of human glycoproteins.