33211-90-4Relevant articles and documents
High fidelity kinetic self-sorting in multi-component systems based on guests with multiple binding epitopes
Mukhopadhyay, Pritam,Zavalij, Peter Y.,Isaacs, Lyle
, p. 14093 - 14102 (2006)
The molecular recognition platforms of natural systems often possess multiple binding epitopes, each of which has programmed functional consequences. We report the dynamic behavior of a system comprising CB[6], CB[7], and guests cyclohexanediammonium (1) and adamantanealkylammonium (2) that we refer to as a two-faced guest because it contains two distinct binding epitopes. We find that the presence of the two-faced guest-just as is observed for protein targeting in vivo-dictates the kinetic pathway that the system follows toward equilibrium. The influence of two-faced guest structure, cation concentration, cation identity, and individual rate and equilibrium constants on the behavior of the system was explored by a combination of experiment and simulation. Deconstruction of this system led to the discovery of an anomalous host-guest complex (CB[6]·1) whose dissociation rate constant (kout = 8.5 × 10-10 s-1) is ≈100-fold slower than the widely used avidin-biotin affinity pair. This result, in combination with the analysis of previous systems which uncovered extraordinarily tight binding events (Ka ≥ 1012 M-1), highlights the inherent potential of pursuing a systems approach toward supramolecular chemistry.