The Structural and Energetic Basis of Carbohydrate-Aromatic Packing Interactions in Proteins.

Journal of the American Chemical Society (Impact Factor: 11.44). 06/2013; 135(26). DOI: 10.1021/ja4040472
Source: PubMed

ABSTRACT Carbohydrate-aromatic interactions mediate many biological processes. However, the structure-energy relationships underpinning direct carbohydrate-aromatic packing in aqueous solution have been difficult to assess experimentally and remain elusive. Here, we determine the structures and folding energetics of chemically synthesized glycoproteins to quantify the contributions of the hydrophobic effect and CH-π interactions to carbohydrate-aromatic packing interactions in proteins. We find that the hydrophobic effect contributes significantly to protein-carbohydrate interactions. Interactions between carbohydrates and aromatic amino acid side chains, however, are supplemented by CH-π interactions. The strengths of experimentally determined carbohydrate-π interactions do not correlate with the electrostatic properties of the involved aromatic residues, suggesting that the electrostatic component of CH-π interactions in aqueous solution is small. Thus, tight binding of carbohydrates and aromatic residues is driven by the hydrophobic effect and CH-π interactions featuring a dominating dispersive component.

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May 28, 2014