Exploring Carbohydrate鈭扨eptide Interactions in the Gas Phase: Structure and Selectivity in Complexes of Pyranosides with N-Acetylphenylalanine Methylamide

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• 作者：Emilio J. Cocinero ; Pierre 脟ar莽abal ; Timothy D. Vaden ; Benjamin G. Davis ; John P. Simons
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：March 30, 2011
• 年：2011
• 卷：133
• 期：12
• 页码：4548-4557
• 全文大小：1159K
• 年卷期：v.133,no.12(March 30, 2011)
• ISSN：1520-5126

文摘

The physical basis of carbohydrate鈭抪eptide interactions has been explored by probing the structures of a series of complexes generated in a solvent-free environment under molecular beam conditions. A combination of double-resonance IR鈭扷V spectroscopy and quantum-chemical calculations has established the structures of complexes of the model, N-acetyl-L-phenylalanine methylamide, bound to the 伪 and 尾 anomers of methyl d-gluco- and d-galactopyranoside as guests. In all cases, the carbohydrates are bound through hydrogen bonding to the dipeptide chain, although with some differing patterns. The amino acid host 鈥渆ngages鈥?with the most suitable pair of neighboring conjugate sites on each carbohydrate; the specific choice depends on the conformation of the peptide backbone and the configuration and conformation of the carbohydrate ligand. None of the structures is supported by 鈥渟tacking鈥?interactions with the aromatic ring, despite their common occurrence in bound carbohydrate鈭抪rotein structures.