Supramolecular Host:Guest Arrays Site-Selectively Recognize Peptide Phosphorylation and Kinase Activity.

A synergistic combination of cationic styrylpyridinium dyes and water-soluble deep cavitand hosts can recognize phosphorylated peptides with both site- and state-selectivity. Two mechanisms of interaction are dominant: either the cationic dye interacts with Trp residues in the peptide or the host:dye pair forms a heteroternary complex with the peptide, driven by both strong dye-peptide and cavitand-peptide binding ( values up to 4 μM). The presence of multiple recognition mechanisms results in varying fluorescence responses dependent on the phosphorylation state and position, eliminating the need for covalent modification of the peptide target.

Optical discrimination of terpenes in citrus peels with a host:guest sensing array.

A simple aqueous host:guest sensing array can selectively discriminate between different types of citrus varietal from peel extract samples. It can also distinguish between identical citrus samples at varying stages of ripening. The discrimination effects stem from detection of changes in the terpenoid composition of the peel extracts by the host:guest array, despite the overwhelming excess of a single component, limonene, in each sample.

Investigation of the effects on proton relaxation times upon encapsulation in a water-soluble synthetic receptor.

Sequestration of small molecule guests in the cavity of a water-soluble deep cavitand host has a variety of effects on their NMR properties. The effects of encapsulation on the longitudinal () and transverse () relaxation times of the protons in variably sized guest molecules are analyzed here, using inversion recovery and spin-echo experiments. Sequestration of neutral organic species from the bulk solvent reduces the overall proton relaxation times, but the magnitude of this effect on different protons in the same molecule has a variety of contributors, from the motion of the guest when bound, to the position of the protons in the cavity and the magnetic anisotropy induced by the aromatic walls of the host.