Selective recognition of sulfate ions by tripodal cyclic peptides functionalised with (thio)urea binding sites

Abstract

A tripodal urea and tripodal thiourea with the same cyclic peptide core have been synthesised and their anion binding ability investigated. In CDCl(3), the tripodal urea self-associates whereas the thiourea does not. Neither compound shows self-association in the more polar 10% v/v DMSO-d(6)/CDCl(3). Both compounds bind strongly and selectively to sulfate ions in CDCl(3) and 10% v/v DMSO-d(6)/CDCl(3). This selectivity is attributed to a unique binding mode for sulfate, in which this tetrahedral anion forms nine hydrogen bonds to the receptors, with three of these coming from the amide protons of the cyclic peptide.

Inhibition of histone binding by supramolecular hosts

“…The plate emission was read (100 reads/well) between 445 and 600 nm and excitation was set to 369 nm. The λ max of the fluorescence readout was selected (485 nm) and these data was fitted with the program Equilibria (http://www.sseau.unsw.edu.au) [26]. See Figure 2(a) and Supplementary Table S1 for results and Supplementary Figure S2 for all titration data and fits (Supplementary Online data available at http://www.biochemj.org/bj/459/bj4590505add.htm).…”

Anion binding with urea and thiourea derivatives

“…Thus, the first anion formed the complex with 117 by binding to a two armed side while the second anion bound to the single armed thiourea side. Further examples of preorganized tripodal (thio)urea receptors were prepared by Jolliffe et al[134].They synthesized receptors based on C 3 -symmetric cyclic peptides and investigated anion Structure of receptor 117.…”

Amino acid-based squaramides for anion recognition

“…However, synthetic peptide-based anion receptors have received surprisingly little attention as membrane transport candidates. We have developed a number of highly efficient and selective anion receptors that can be constructed from a small number of amino acid building blocks to accommodate a variety of target anionic guests (7)(8)(9)(10). The ability of these receptors to discriminate between anions has inspired us to examine their use as anion transporters and we have recently reported the design and synthesis of peptide-based cryptands that we demonstrated to act as efficient SO 22 4 transporters (10).…”