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PDBsum entry 2nc5
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References listed in PDB file
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Key reference
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Title
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The dependence of carbohydrate-Aromatic interaction strengths on the structure of the carbohydrate.
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Authors
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C.H.Hsu,
S.Park,
D.E.Mortenson,
B.L.Foley,
X.Wang,
R.J.Woods,
D.A.Case,
E.T.Powers,
C.H.Wong,
H.J.Dyson,
J.W.Kelly.
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Ref.
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J Am Chem Soc, 2016,
138,
7636-7648.
[DOI no: ]
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PubMed id
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Abstract
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Interactions between proteins and carbohydrates are ubiquitous in biology.
Therefore, understanding the factors that determine their affinity and
selectivity are correspondingly important. Herein, we have determined the
relative strengths of intramolecular interactions between a series of
monosaccharides and an aromatic ring close to the glycosylation site in an
N-glycoprotein host. We employed the enhanced aromatic sequon, a structural
motif found in the reverse turns of some N-glycoproteins, to facilitate
face-to-face monosaccharide-aromatic interactions. A protein host was used
because the dependence of the folding energetics on the identity of the
monosaccharide can be accurately measured to assess the strength of the
carbohydrate-aromatic interaction. Our data demonstrate that the
carbohydrate-aromatic interaction strengths are moderately affected by changes
in the stereochemistry and identity of the substituents on the pyranose rings of
the sugars. Galactose seems to make the weakest and allose the strongest
sugar-aromatic interactions, with glucose, N-acetylglucosamine (GlcNAc) and
mannose in between. The NMR solution structures of several of the
monosaccharide-containing N-glycoproteins were solved to further understand the
origins of the similarities and differences between the monosaccharide-aromatic
interaction energies. Peracetylation of the monosaccharides substantially
increases the strength of the sugar-aromatic interaction in the context of our
N-glycoprotein host. Finally, we discuss our results in light of recent
literature regarding the contribution of electrostatics to CH-π interactions
and speculate on what our observations imply about the absolute conservation of
GlcNAc as the monosaccharide through which N-linked glycans are attached to
glycoproteins in eukaryotes.
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