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Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Hydrogen-bonding behavior of amidines in helical structure
Emily A O'Brien1, Jeffrey A Purslow1, Brendan J Wall1
1Department of Chemistry, Iowa State University Ames IA 50011 USA bvv@iastate.edu.
Abstract:
Amidines are an isostere of the amide bond and are completely unexplored in peptide secondary structure. This study marks the first investigation of the structural implications of amidines in folded helices. Amidines were found to engage in hydrogen-bonding interactions that are compatible with helical structure. The protic state of the amidine is also adaptive to local interactions, able to form stronger hydrogen bonds with proton donors or form the first example of a salt bridge along the peptide backbone to stabilize the C-terminus of the helical fold. The rationalization of this behavior was aided by our discovery that the basicity of amidines within peptide backbones can be significantly lower than previously assumed for small molecules. These findings compel investigation of amidines in peptide-drug design.
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