Cucurbit[7]uril (Q7) is a synthetic host molecules that binds with high affinity to a wide range of guests in aqueous solution, including peptides and proteins. Prior studies of Q7 binding with insulin fragments in the gas phase led to an interesting semiempirical model in which the N-terminal phenylalanine binds within the cavity, and the rest of the peptide wraps around the outside of Q7 to allow the histidine at position 10 to interact with the opposite portal of Q7. Inspired by this study, we measured the binding of Q7 to the insulin B1-11 peptide and two single mutants in aqueous solution by CD and NMR spectroscopy and obtained evidence consistent with the gas-phase binding model. Moreover, the His residue enhanced the binding affinity, thereby demonstrating a rare example of peptide recognition mediated by simultaneous interaction with two distant residues.

Induced-fit binding of cucurbit[7]uril to insulin B1-11 in aqueous solution

253rd National Meeting (2017)

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