Anion Binding Research Articles

Two new dilactonized glycerol glycosides of the dual anticholinesterase active extract from Ocotea daphnifolia using bioguided fractionation and molecular docking studies.

The dual inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) is considered as an important strategy for the treatment of Alzheimer's disease. In this study, we applied the bioguided fractionations of Ocotea daphinifolia ethyl acetate active extract to furnish a fraction with high inhibitory activity for AChE and BuChE (82% and 92%, respectively). High-performance liquid chromatography semipreparative purification of this fraction provided two new natural products: 1-β-D-galactopyranosyl-glycerol-2,3-heptanedionate, (1) whose complete chemical structural elucidation was made with spectrometric analysis (MS, 1D, and 2D NMR) and its minor derivative 1-β-D-gulopyranosyl-glycerol-2,3-heptanedionate; (2) which could be characterized by 2D 1 H-13 C heteronuclear single-quantum correlation spectra analysis. Investigation of the intermolecular interactions with cholinesterases was carried out by molecular docking studies, and results suggested that both compounds are capable to interact with the catalytic site of both enzymes. Compounds 1 and 2 interact with residues of catalytic domains and the peripheral anionic binding site of AChE and BuChE. The results are comparable to those achieved with rivastigmine and galantamine. Thus, this study provides evidence for consideration of the glycosylglycerol from O. daphnifolia as new valuable dual cholinesterases inhibitor.

Effect of oxygen heteroatom on sensor-cyanide anions binding

The study aims to analyze the effect of heteroatom replacement on benzimidazole derivative chemosensor compounds on the ability to form hydrogen bonds with anions. In this case, the N heteroatom in the benzimidazole derivative sensor compound (S1) is replaced with the O heteroatom to become a benzoxazole derivative sensor compound (S3). Calculating the energy of the molecules involved in the electron level gives the following results: replacing heteroatoms with more electronegative atoms increases the HOMO energy of the sensor molecules, making the sensor more reactive to anions and strengthening the binding of the sensor with cyanide anions.

Molecular Pincers Using a Combination of N-H and C-H Donors for Anion Binding.

A naphthalene imide (1) and a naphthalene (2) bearing two pyrrole units have been synthesized, respectively, as anion receptors. It was revealed by 1H NMR spectral studies carried out in CD3CN that receptors 1 and 2 bind various anions via hydrogen bonds using both C-H and N-H donors. Compared with receptor 2, receptor 1 shows higher affinity for the test anions because of the enhanced acidity of its pyrrole NH and naphthalene CH hydrogens by the electron-withdrawing imide substituent. Molecular mechanics computations demonstrate that the receptors contact the halide anions via only one of the two respective available N-H and C-H donors whereas they use all four donors for binding of the oxyanions such as dihydrogen phosphate and hydrogen pyrophosphate. Receptor 1, a push-pull conjugated system, displays a strong fluorescence centered at 625 nm, while receptor 2 exhibits an emission with a maximum peak at 408 nm. In contrast, upon exposure of receptors 1 and 2 to the anions in question, their fluorescence was noticeably quenched particularly with relatively basic anions including F-, H2PO4-, HP2O73-, and HCO3-.

Anion Binding as a Strategy for the Synthesis of Porous Salts.

Porous salts have recently emerged as a promising new class of ultratunable permanently microporous solids. These adsorbents, which were first reported as ionic solids based on porous cations and anions, can be isolated from a wide variety of charged, permanently porous coordination cages. A challenge in realizing the full tunability of such systems, however, lies in the fact that the majority of coordination cages for which surface areas have been reported are comprised of charge-balanced inorganic and organic building blocks that result in neutral cages. As such, most reported permanently porous coordination cages cannot be used as reagents in the synthesis of porous salts. Here, we show that the facile reaction of TBAX (TBA+ = tetra-n-butylammonium; X = F- and Cl-) with molybdenum paddlewheel-based coordination cages of the M4L4 and M24L24 lantern and cuboctahedra structure types, respectively, affords charged cages by virtue of coordination of halide anions to the internal and/or external metal sites on these structures, as confirmed by single-crystal X-ray diffraction, X-ray photoelectron spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. At a practical level, the TBAX/cage reactions, which are fully reversible upon isolation of the cage with the appropriate solvent, solubilize otherwise rigorously insoluble cages. This method significantly increases the solution processability of these highly porous solids. Toward the formation of new porous salts, halide binding also serves to incorporate charge on neutral cages and make them amenable to simple salt metathesis reactions to afford new porous salts based on anions and cations with intrinsic porosity. A combination of diffraction methods and a suite of spectroscopic tools confirms speciation of the isolated solids, which represent a new class of highly tunable porous salts. Ultimately, this work represents a roadmap for the preparation of new porous solids and showcases the utility and broad applicability of anion binding as a strategy for the synthesis of porous salts.

Chemo diversity of ginger-a potent crop in Manipur and its acetylcholinesterase (AChE) inhibitory potential

The rate of neurodegenerative diseases such as Alzheimer's disease (AD) is rising, particularly in older people. Several medicines are available to temporarily ameliorate the signs of AD but due to adverse effects and inadequate efficacy, there is a need to search for new compounds. Zingiber officinale Roscoe (ginger) is well known for its abundant valuable medicinal properties which might be suitable for the treatment and management of AD. The extracted essential ginger oils from eight samples of Z. officinale from different locations of Senapati district, Manipur were aimed to identify the oil constituents and evaluate the acetylcholinesterase (AChE) inhibitory activity. All the ginger oils were standardized and the major compound (α-citral) was quantified in each oil. Six major volatile compounds (common in all the oils) were further studied through molecular docking analysis to evaluate the possible binding interaction profile with the acetylcholinesterase (AChE) enzyme. Gas chromatography-mass spectrometry (GC-MS) analysis of oils revealed that α-citral is the most abundant chemical constituent in all ginger oils ranging from 13.92 to 30.46%. α-citral, camphene, geraniol, α-pinene, linalool, and α-citronellol were commonly present in all eight ginger oils. Sample M1 showed the highest activity (IC50 = 51.12 ± 0.37 μg/ml; ***P < 0.001) while the lowest activity was observed in Sample M7 (IC50 = 84.47 ± 0.29 μg/ml; ***P < 0.001) against AChE activity. The AChE inhibition activity of chemical constituents was decreased in the following order: linalool > camphene > α-citronellol > α-citral > geraniol > α-pinene. The percentage of marker compound (α-citral) in ginger oil was found maximum in sample M1 (243.9 ± 3.1 μg/mg) and minimum in sample M5 (111.33 ± 1.5 μg/mg). It was observed that all six chemical compounds perfectly occupied the biologically relevant several subsites region, such as the oxyanion hole, anionic subsite binding pocket, or peripheral anionic site (PAS) of the AChE protein. Our results highlight the chemo diversity of ginger available in Manipur and its importance as a potential AChE inhibitor.

Integrated Transcriptome Analysis Reveals the Crucial mRNAs and miRNAs Related to Fecundity in the Hypothalamus of Yunshang Black Goats during the Luteal Phase.

A normal estrus cycle is essential for the breeding of goats, and the luteal phase accounts for most of the estrus cycle. The corpus luteum (CL) formed during the luteal phase is a transient endocrine gland that is crucial for the reproductive cycle and pregnancy maintenance, and is controlled by many regulatory factors. However, the molecular mechanism of the hypothalamus effect on the reproductive performance of different litter sizes during the luteal phase of goats has not been elucidated. In this study, RNA-sequencing was used to analyze the mRNA and miRNA expression profiles of the hypothalamic tissues with the high-fecundity goats during the luteal phase (LP-HF) and low-fecundity goats during the luteal phase (LP-LF). The RNA-seq results found that there were 1963 differentially expressed genes (DEGs) (890 up-regulated and 1073 down-regulated). The miRNA-seq identified 57 differentially expressed miRNAs (DEMs), including 11 up-regulated and 46 down-regulated, of which 199 DEGs were predicted to be potential target genes of DEMs. Meanwhile, the functional enrichment analysis identified several mRNA-miRNA pairs involved in the regulation of the hypothalamic activity, such as the common target gene MEA1 of novel-miR-972, novel-miR-125 and novel-miR-403, which can play a certain role as a related gene of the reproductive development in the hypothalamic-pituitary-gonadal (HPG) axis and its regulated network, by regulating the androgen secretion. While another target gene ADIPOR2 of the novel-miR-403, is distributed in the hypothalamus and affects the reproductive system through a central role on the HPG axis and a peripheral role in the gonadal tissue. An annotation analysis of the DE miRNA-mRNA pairs identified targets related to biological processes, such as anion binding (GO:0043168) and small molecule binding (GO: 0036094). Subsequently, the KEGG(Kyoto Encyclopedia of Genes and Genomes) pathways were performed to analyze the miRNA-mRNA pairs with negatively correlated miRNAs. We found that the GnRH signaling pathway (ko04912), the estrogen signaling pathway (ko04915), the Fc gamma R-mediated phagocytosis (ko04666), and the IL-17 signaling pathway (ko04657), etc., were directly and indirectly associated with the reproductive process. These targeting interactions may be closely related to the reproductive performance of goats. The results of this study provide a reference for further research on the molecular regulation mechanism for the high fertility in goats.

Application for the porous structure of cellulose separators: Ionic conduction path in lithium-ion battery

In lithium-ion batteries, separator is an important component as its porous structure is the ionic conduction path. Renewable biomacromolecule cellulose separators have pores that can be modified, and the modification has the potential to affect ion conduction. In this work, functionalized separators based on cellulose are prepared, which can affect the conduction behavior of ions. The cellulose separators TF4030 are firstly Atomic Layer Deposition (ALD) treated to get a silica reinforcement coating layer on the cellulose fibers; then, the ALD layer is further chemically modified to graft specific boron-containing groups -NH-B(OH) 2 and form a functional structure on the surface of cellulose fibers. The conduction of lithium-ions is promoted due to the widely distributed electron-deficient boronic groups in the pores of the separator, reflected as the increased lithium-ion transference number of 0.48. Proved by Density Functional Theory (DFT) Calculations, the essential reason for this phenomenon is that the binding of electron-deficient boron groups and anions weakens the conduction of anions as well as the binding of electron-deficient boron groups and solvents influences the desolvation of lithium-ions in electrolytes. As a result, batteries assembled with functionalized cellulose separators have better battery performances, including cycle stability and capacity retention at high current rates.

Relevance of the Cation in Anion Binding of a Triazole Host: An Analysis by Electrophoretic Nuclear Magnetic Resonance.

Triazole hosts allow cooperative binding of anions via hydrogen bonds, which makes them versatile systems for application in anion binding catalysis to be performed in organic solvents. The anion binding behavior of a tetratriazole host is systematically studied by employing a variety of salts, including chloride, acetate, and benzoate, as well as different cations. Classical nuclear magnetic resonance (1H NMR) titrations demonstrate a large influence of cation structures on the anion binding constant, which is attributed to poor dissociation of most salts in organic solvents and corrupts the results of classical titration techniques. We propose an approach employing electrophoretic NMR (eNMR), yielding drift velocities of each species in an electric field and thus allowing a distinction between charged and uncharged species. After the determination of the dissociation constants KD for the salts, electrophoretic mobilities are measured for all species in the host-salt system and are analyzed in a model which treats anion binding as a consecutive reaction to salt dissociation, yielding a corrected anion binding constant KA. Interestingly, dependence of KA on salt concentration occurs, which is attributed to cation aggregation with the anion-host complex. Finally, by the extrapolation to zero salt concentration, the true anion-host binding constant is obtained. Thus, the approach by eNMR allows a fully quantitative analysis of two factors that might impair classical anion binding studies, namely, an incomplete salt dissociation as well as the occurrence of larger aggregate species.

A Novel Substrate for Assessing Thrombin Activity in Whole Blood

At sites of vessel injury, thrombin acts as the central mediator of coagulation through catalyzing fibrin clot formation and platelet activation. Currently, thrombin generation is measured using small molecule substrates. These substrates are limited in that they detect both active thrombin and thrombin bound to its inhibitor α2-macroglobulin (α2-M) and have limited utility in whole blood (Ninivaggi et al. Clin Chem 2012). In addition, these substrates contain short thrombin recognition sequences ranging from 3-4 amino acids and are unable to form additional exosite interactions with thrombin, which limit their specificity (Gallwitz et al. Plos One 2012). Furthermore, they are unfeasible for in vivo use because their hydrophobicity allows them to enter cells. However, plasma assays are limited because they ignore the hemostatic contributions of red blood cells, platelets and leukocytes and require anticoagulation and the addition of exogenous coagulation activators (Swystun & Liaw. Blood 2016 & do Amaral et al. Stem Cells Int 2016). Thus, we have developed a fluorescence resonance energy transfer (FRET)-based thrombin sensor to overcome these limitations. We cloned and expressed the construct encoding the FRET-based thrombin substrate in Escherichia coli and purified the substrate using affinity chromatography. We confirmed using Sodium dodecyl sulfate−polyacrylamide gel electrophoresis that the substrate was successfully purified and that thrombin cleavage of the purified substrate changes its FRET efficiency by monitoring its spectrum of emission. To determine whether the FRET-based thrombin substrate can form interactions with thrombin's anion binding exosites and assess its potential for in vivo use, we measured the kinetics parameters of the substrate for thrombin in the presence of exosite inhibitors and thrombin's exosite variants as well as mouse thrombin and plasmin. We then compared the resulting kinetics parameters with commercially available thrombin substrates S2238 and technothrombin. We show that unlike S2238 and technothrombin, our FRET-based thrombin sensor forms strong interactions with thrombin's anion binding exosite I and displays preference for free thrombin compared to thrombomodulin (TM) bound thrombin which implied its preference for procoagulant thrombin rather than anticoagulant TM bound thrombin that activates protein C. Furthermore, our FRET-based thrombin substrate has potential to be used in mouse models because it can be efficiently cleaved by mouse thrombin and is relatively plasmin resistant. To assess the specificity of the FRET-based thrombin substrate for thrombin, we compared the rate of hydrolysis of the substrate by thrombin and several other enzymes in circulation and compared the results to S2238 and technothrombin. Our results indicated that when compared to commercially available thrombin substrates, our FRET-based thrombin substrate is highly specific for thrombin. Since the thrombin inhibitor α2-M is present in circulation, we also compared the rate of hydrolysis of the 3 substrates for α2-M bound thrombin and free thrombin. Unlike S2238 and technothrombin, our FRET-based thrombin substrate is uncleaved by α2-M bound thrombin. The key properties of the FRET-based thrombin substrate in comparison to S22238 and technothrombin are summarized in Table 1. We then measured thrombin generation in plasma using our FRET-based thrombin substrate and showed that it is sensitive to direct oral anticoagulants in ways that are consistent with literature findings where thrombin generation was measured using technothrombin (Sivaraja et al. Plos One 2018 & Douxfils et al. Thromb Res 2012). We also confirmed that the FRET-based thrombin substrate itself is not a coagulation inhibitor since its presence did not alter thrombin generation parameters measured using technothrombin. Lastly, we confirmed that the FRET-based thrombin substrate can measure thrombin generation in whole blood since it successfully produced thrombin generation curves. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Directional regulation of cytosolic PEPCK catalysis is mediated by competitive binding of anions

Phosphoenolpyruvate carboxykinase (PEPCK) is a well-characterized enzyme involved in primary glucose metabolism, responsible for catalyzing one of the key steps of gluconeogenesis. It is well demonstrated that PEPCK can efficiently catalyze the reversible interconversion of oxaloacetic acid (OAA) to phosphoenolpyruvate (PEP) in vitro, but the enzyme is typically ascribed a metabolic role that requires preferential catalysis in the direction of PEP synthesis in vivo. Here we present structural and functional data that demonstrate the preferential synthesis of PEP from OAA catalyzed by PEPCK in vivo is facilitated by anion-mediated enzyme inhibition that reduces enzyme activity more significantly in the direction of OAA synthesis than in the direction of PEP synthesis. From our studies we conclude that the specific binding of small, ubiquitous anions like chloride, present in millimolar concentrations under normal cellular conditions allows for metabolic control by restricting PEPCK to function in the direction of PEP synthesis.

Helicate tris(aryl)carbinolates bearing pendant NR2 donors – a new family of supporting ligands for the synthesis of Sc3+ alkyl complexes

The reactions of aryllithium reagents o-LiC6H4CH2NR2 with (MeO)2CO afford two new tris(aryl)carbinols bearing pendant-NR2 donor groups in the side chain [o-R NCH C H ] COH [R = Me, R + R = (CH) ]. These alcohols feature helical chirality due to differently inclined aromatic fragments and are presented in a crystalline cell as two M and P enantiomers. Carbinol (R = Me) readily reacts with (Me3SiCH2)3Sc(THF)2 to give a scandium bis(alkyl) complex [(o-C6H4CH2NMe2)3CO]Sc(CH2SiMe3)2 featuring rigid binding of the alkoxy anion through a κ1-O, κ2-N chelating coordination mode

Selective Recognition and Reversible “Turn-Off” Fluorescence Sensing of Acetate (CH3COO−) Anion at Ppb Level Using a Simple Quinizarin Fluorescent Dye

A simple and cost-effective optical sensing system based on quinizarin fluorescent dye (QZ) for the selective and reversible sensing of CH3COO− anions is reported. The anion binding affinity of QZ towards different anions was monitored using electronic absorption and fluorescence emission titration studies in DMSO. The UV-visible absorption spectrum of QZ showed a decrease in the intensity of the characteristic absorption peaks at λ = 280, 323, and 475 nm, while a new peak appeared at λ = 586 nm after the addition of CH3COO− anions. Similarly, the initial strong emission intensity of QZ was attenuated following titration with CH3COO− anions. Notably, similar titration using other anions, such as F−, Cl−, I−, NO3−, NO2−, and H2PO4-, caused no observable changes in both absorption and emission spectra. The selective sensing of CH3COO− anions was also reflected by a sharp visual color change from bright green to faint green under room light. Further, the binding was found to be reversible, and this makes QZ a potential optical and colorimetric sensor for selective, reversible, and ppb-level detection of CH3COO− anions in a DMSO medium.

Functional Characterization of Saccharomyces cerevisiae P5C Reductase, the Enzyme at the Converging Point of Proline and Arginine Metabolism.

The enzyme that, in Saccharomyces cerevisiae, catalyzes the last step in both proline synthesis and arginine catabolism, δ1-pyrroline-5-carboxylate (P5C) reductase, was purified to near homogeneity and characterized thoroughly. Retention patterns upon gel permeation chromatography were consistent with a homodecameric composition of the holomer. High lability of the purified preparations and stabilization by reducing compounds suggested susceptibility to reactive-oxygen-species-mediated damage. Both NADH and NADPH were used as the electron donor, the latter resulting in a 3-fold higher Vmax. However, a higher affinity toward NADH was evident, and the NADPH-dependent activity was inhibited by NAD+, proline, arginine, and a variety of anions. With proline and arginine, the inhibition was of the competitive type with respect to the specific substrate, and of the uncompetitive- or mixed-type with respect to NADPH, respectively. The results suggest that, contrary to the enzyme from higher plants, yeast P5C reductase may preferentially use NADH in vivo. An in silico analysis was also performed to investigate the structural basis of such enzyme features. Superposition of the protein model with the experimental structure of P5C reductase from Medicago truncatula allowed us to hypothesize on the possible allosteric sites for arginine and anion binding, and the cysteine pairs that may be involved in disulfide formation.

Artificial Water Channels—Progress Innovations and Prospects

Artificial Water Channels—Progress Innovations and Prospects

Head vs. Tail Squaramide–Naphthalimide Conjugates: Self-Assembly and Anion Binding Behaviour

The syntheses of two squaramide–naphthalimide conjugates (SN1 and SN2) are reported; the structures of SN1 and SN2 differ by the attachment of a squaramide—either at the ‘head’ or the ‘tail’ of the naphthalimide fluorophore. Both compounds displayed weak fluorescence due to the inclusion of a nitro-aromatic squaramide which efficiently quenches the emission of the naphthalimide. Both compounds were also shown to undergo self-aggregation as studied by 1H NMR and scanning electron microscopy (SEM). Furthermore, SN1 and SN2 gave rise to stark colourimetric changes in response to basic anions such as AcO−, SO42− HPO42−, and F−. The observed colour changes are thought to be due to deprotonation of a squaramide NH. The same basic anions also result in a further quenching of the naphthalimide emission. No colour change or emission modulations were observed in the presence of Cl−; however, 1H NMR studies suggest that moderate H-bonding occurs between this anion and both SN1 and SN2.

Tuning anion binding properties of Bis(indolyl)methane Receptors: Effect of substitutions on optical responses

Chromogenic probes based onoxidizedbis(indolyl)methanes have been synthesized with varying substituents (R = -Me [1], -OMe [2], –OH, [3]) on the central aryl ring. In addition to electronic influence, the involvement of substituents in ion–dipole and charge-assisted hydrogen bonding interactions significantly alters the solvatochromic response and pH-sensitive behavior. In polar aprotic solvents, like CH3CN, a concentration-dependent stepwise color change was observed with F- ions. In the case of2, a reversible hydrogen bonding interaction between the deprotonated probe and HF2- dimer might be responsible for that, while step-wise deprotonation caused by F- ions could be the probable reason with3. Since the formation of HF2- is energetically unfavorable in a polar protic solvent, the response of 2 with F- ions appears to be very different in EtOH medium. Interestingly, no such alteration in anion sensing behavior was noticed with3going from an aprotic to a protic solvent.

Anion Recognition with Antimony(III) and Bismuth(III) Triaryl-Based Pnictogen Bonding Receptors.

The synthesis and characterisation of a library of acyclic antimony(III) and bismuth(III) triaryl pnictogen bonding (PnB) receptor systems are reported. In the first-generation receptor series, quantitative 1 H NMR chloride titration experiments in THF solvent media reveal halide anion binding potency is intimately correlated with both the electronic-withdrawing nature of the aryl- substituent and the polarisability of the PnB donor. Further extensive anion binding investigations with the most potent Sb- and Bi-based PnB receptors: 1⋅Sb2CF3 and 1⋅Bi2CF3 , reveal novel selectivity profiles, both displaying Cl- selectivity relative to the heavier halides and, impressively, to a range of highly basic oxoanions. The synthesis and preliminary chloride anion binding studies of a series of novel tripodal tris-proto-triazole triaryl Sb(III) and Bi(III) mixed PnB-HB receptor systems are also described. Whereas parent triphenyl Sb(III) and Bi(III) compounds are incapable of binding Cl- in THF solvent media, the PnB-triazole HB host systems exhibit notable halide affinity.

Cryo-electron microscopy unveils unique structural features of the human Kir2.1 channel.

We present the first structure of the human Kir2.1 channel containing both transmembrane domain (TMD) and cytoplasmic domain (CTD). Kir2.1 channels are strongly inward-rectifying potassium channels that play a key role in maintaining resting membrane potential. Their gating is modulated by phosphatidylinositol 4,5-bisphosphate (PIP2). Genetically inherited defects in Kir2.1 channels are responsible for several rare human diseases, including Andersen’s syndrome. The structural analysis (cryo–electron microscopy), surface plasmon resonance, and electrophysiological experiments revealed a well-connected network of interactions between the PIP2-binding site and the G-loop through residues R312 and H221. In addition, molecular dynamics simulations and normal mode analysis showed the intrinsic tendency of the CTD to tether to the TMD and a movement of the secondary anionic binding site to the membrane even without PIP2. Our results revealed structural features unique to human Kir2.1 and provided insights into the connection between G-loop and gating and the pathological mechanisms associated with this channel.

Highly Efficient and Selective Recognition of Dicyanoaurate(I) by a Bambusuril Macrocycle in Water.

Dicyanoaurate(I) anion, [Au(CN)2 ]- , plays a central role in the current industrial production of gold, as its extraction from crude ore samples represents the most money-consuming step. Herein, we present the strongest host-guest recognition of dicyanoaurate anion using the bambusuril receptor in water, a highly competitive solvent. The micromolar stability of such a complex facilitated the up to date most efficient supramolecular stripping of dicyanoaurate from activated carbon at ambient temperature. Thermodynamic characteristics of bambusuril binding with [Au(CN)2 ]- differing from binding of other inorganic chaotropic anions are rationalized, as well as the bambusuril selectivity for [Au(CN)2 ]- over [Ag(CN)2 ]- .

Highly Efficient and Selective Recognition of Dicyanoaurate(I) by a Bambusuril Macrocycle in Water

AbstractDicyanoaurate(I) anion, [Au(CN)2]−, plays a central role in the current industrial production of gold, as its extraction from crude ore samples represents the most money‐consuming step. Herein, we present the strongest host–guest recognition of dicyanoaurate anion using the bambusuril receptor in water, a highly competitive solvent. The micromolar stability of such a complex facilitated the up to date most efficient supramolecular stripping of dicyanoaurate from activated carbon at ambient temperature. Thermodynamic characteristics of bambusuril binding with [Au(CN)2]− differing from binding of other inorganic chaotropic anions are rationalized, as well as the bambusuril selectivity for [Au(CN)2]− over [Ag(CN)2]−.