A Threaded Loop Conformation Adopted by a Family of Peptoid Nonamers

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• 作者：Kai Huang ; Cindy W. Wu ; Tracy J. Sanborn ; James A. Patch ; Kent Kirshenbaum ; Ronald N. Zuckermann ; Annelise E. Barron ; and Ishwar Radhakrishnan
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：February 8, 2006
• 年：2006
• 卷：128
• 期：5
• 页码：1733 - 1738
• 全文大小：376K
• 年卷期：v.128,no.5(February 8, 2006)
• ISSN：1520-5126

文摘

Non-natural polymers with well-defined three-dimensional folds offer considerable potential forengineering novel functions that are outside the scope of biological polymers. Here we describe a familyof N-substituted glycine or "peptoid" nonamers that folds into an unusual "threaded loop" structure ofexceptional thermal stability and conformational homogeneity in acetonitrile. The structure is chain-length-specific and relies on bulky, chiral side chains and chain-terminating functional groups for stability. Notableelements of the structure include the engagement of the positively charged amino terminus by carbonylgroups of the backbone through hydrogen bonding interactions and shielding of polar groups from andnear-complete exposure of hydrophobic groups to solvent, in a manner resembling a folded polypeptideglobular domain turned inside-out. The structure is stable in a variety of organic solvents but is readilydenatured in any solvent/cosolvent milieu with hydrogen bonding potential. The structure could serve as ascaffold for the elaboration of novel functions and could be used to test methodologies for predicting solvent-dependent polymer folding.