Highly Substituted <i>t</i><i>er</i>-Cyclopentanes as Receptors for Lipid A

Hubbard, Robert D.; Horner, Scott R.; Miller, Benjamin L.

doi:10.1021/ja003712y

Cited by 67 publications

(24 citation statements)

References 23 publications

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“…[1][2][3] In addition, synthetic carbohydrate receptors have contributed significantly to our current understanding of the factors that control affinity as well as selectivity in carbohydrate recognition. [4] In spite of the significant progress that has undoubtedly been made in the development of artificial carbohydrate receptors, including the first systems active in aqueous solution, [5][6][7][8][9] practical applications for such receptors, for example as chemosensors to detect the presence and concentration of biologically important sugars in aqueous solution, are not yet in sight. These applications, examples of which are monitoring the glucose level in blood or the sugar concentration during fermentation processes, require a receptor to bind to a given substrate and signal complex formation in water, yet most while D-fructose, D-ribose, and D-xylose cannot be bound by cooperative action of both boronic acid binding sites.…”

Section: Introductionmentioning

confidence: 99%

An Enantioselective Fluorescence Sensor for Glucose Based on a Cyclic Tetrapeptide Containing Two Boronic Acid Binding Sites

2006

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The synthesis and binding properties of carbohydrate receptor 1d, which contains two boronic acid binding sites facing each other at opposing sides of a cyclotetrapeptide cavity, are presented. According to electrospray mass spectrometry, 1H NMR spectroscopy, and fluorescence spectroscopy, this receptor forms stable 1:1 complexes with D‐glucose (Ka = 24800 ± 1200 M–1) and L‐glucose (Ka = 11900 ± 1600 M–1) in water/methanol (1:1) at pH = 11.7. Complexes with D‐galactose, D‐mannose, and D‐allose are significantly less stable, while D‐fructose, D‐ribose, and D‐xylose cannot be bound by cooperative action of both boronic acid binding sites. Thus, 1d possesses high affinity and selectivity in glucose recognition combined with good enantioselectivity. Moreover, fluorescence of 1d is quenched upon substrate binding, which allows the use of this receptor as an optical sensor for glucose in aqueous solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Section: Introductionmentioning

confidence: 99%

An Enantioselective Fluorescence Sensor for Glucose Based on a Cyclic Tetrapeptide Containing Two Boronic Acid Binding Sites

2006

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“…In biology, most carbohydrate recognition involves oligosaccharides, so we were interested to learn if these extended substrates could be addressed by our strategy (22)(23)(24)(25)(26). We therefore considered larger versions of our receptor, aimed at all-equatorial disaccharides such as cellobiose 4 ( Fig.…”

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A Synthetic Lectin Analog for Biomimetic Disaccharide Recognition

Ferrand

Crump

Davis

2007

Science

321

197

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was measured with a physical property measurement system. The electrical resistivity shows the MIT at T c = 154 K on cooling ( Fig. 1) and exhibits large thermal hysteresis behavior indicating a first-order character of the MIT. Ca 1.9 Sr 0.1 RuO 4 crystals for scanning tunneling microscopy (STM), LEED, and HREELS measurements were mounted on the sample plates with conducting silver epoxy, and a small metal post was glued on top. The crystal was cleaved by knocking off the post in ultrahigh vacuum with a base pressure of 1.0 × 10 −10 torr, producing a flat shiny [001] surface that yielded a sharp LEED pattern. The STM images of the freshly cleaved surfaces show large micrometer-sized terraces. Both the LEED pattern and atomically resolved STM images indicate that the surface has a well-ordered lattice structure. All surface steps are integral multiples of~6.4 Å , which is the spacing between two nearest-neighbor RuO6 octahedron layers (Fig. 1) 16. S. Nakatsuji et al., Phys. Rev. Lett. 93, 146401 (2003). 17. Detailed spectral data analysis methods were as follows:The Drude weight is the integrated intensity obtained from the difference between the left and right sides of the quasi-elastic peak through a Lorentzian function. Yann Ferrand, Matthew P. Crump, Anthony P. Davis* Carbohydrate recognition is biologically important but intrinsically challenging, for both nature and host-guest chemists. Saccharides are complex, subtly variable, and camouflaged by hydroxyl groups that hinder discrimination between substrate and water. We have developed a rational strategy for the biomimetic recognition of carbohydrates with all-equatorial stereochemistry (b-glucose, analogs, and homologs) and have now applied it to disaccharides such as cellobiose. Our synthetic receptor showed good affinities, not unlike those of some lectins (carbohydrate-binding proteins). Binding was demonstrated by nuclear magnetic resonance, induced circular dichroism, fluorescence spectroscopy, and calorimetry, all methods giving self-consistent results. Selectivity for the target substrates was exceptional; minor changes to disaccharide structure (for instance, cellobiose to lactose) caused almost complete suppression of complex formation. Carbohydrates are challenging substrates for host-guest chemistry (1-4). They possess extended, complex structures that require large receptor frameworks for full encapsulation. The differences between them are often subtle (e.g., the stereochemistry of a single hydroxyl group), so that meaningful selectivity is hard to achieve. Most particularly they are found in water and, with their arrays of hydroxyl groups, they quite strongly resemble water. The first task of a receptor is to discriminate between solvent and substrate, and in the case of carbohydrates this is clearly nontrivial. There is evidence that even nature finds the problem difficult. Though critical for many biological processes (5-7), protein/carbohydrate binding is remarkably weak (8). For example, lectins, the most common class of natural recepto...

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“…C arbohydrate recognition is an active area of supramolecular chemistry, motivated by the biological importance of saccharides and also by the unusual challenge represented by these complex substrates (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). On the one hand, carbohydrates must be recognized and processed during metabolism, whereas saccharide motifs are known to mediate cell-cell recognition, the infection of cells by pathogens, and many aspects of the immune response (14)(15)(16)(17).…”

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“…In the presence of liquid water, the problem becomes yet more difficult. Recognition by means of boronate formation has been relatively successful (2,(7)(8)(9)(10), but there are few effective systems for binding saccharides from water by using noncovalent bonds (1,(11)(12)(13).…”

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confidence: 99%

Phase transfer of monosaccharides through noncovalent interactions: Selective extraction of glucose by a lipophilic cage receptor

Ryan

Lecollinet²,

Velasco³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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We have previously shown that macrotricyclic host 1a is a powerful receptor for glucopyranosyl units in the nonpolar medium of chloroform. However, the solubility properties of 1a did not permit studies of the extraction of carbohydrates from aqueous solution. This paper describes the synthesis of the new variant 1b, furnished with a highly lipophilic exterior array of 12 benzyloxy substituents. In homogeneous solution, 1b behaves much as 1a, binding n-octyl ␤-D-glucoside with Ka ‫؍‬ 720 M ؊1 in CD3OH͞CDCl3 (8:92). In twophase experiments, the improved solubility of 1b allows carbohydrate extraction to be observed. Three hexoses (glucose, galactose, and mannose), two pentoses (ribose and xylose), and the two methyl glucosides are all extracted substantially into chloroform from 1 M aqueous solutions. Among the hexoses, 1b shows notable affinity and selectivity for glucose, extracting detectable amounts even from 0.1 M aqueous solutions. C arbohydrate recognition is an active area of supramolecular chemistry, motivated by the biological importance of saccharides and also by the unusual challenge represented by these complex substrates (1-13). On the one hand, carbohydrates must be recognized and processed during metabolism, whereas saccharide motifs are known to mediate cell-cell recognition, the infection of cells by pathogens, and many aspects of the immune response (14-17). On the other, carbohydrates possess structures that are fairly large, irregular, and multivalent, while being quite similar to clusters of water molecules. Even in nonpolar solvents, selective carbohydrate receptors require extended, sophisticated architectures (1, 3-6). In the presence of liquid water, the problem becomes yet more difficult. Recognition by means of boronate formation has been relatively successful (2, 7-10), but there are few effective systems for binding saccharides from water by using noncovalent bonds (1, 11-13).A receptor can be shown to discriminate between saccharide and water in one of two ways. Firstly (and most obviously), it can be studied in homogeneous aqueous solution. Secondly, it can be designed for solubility in nonpolar media and studied in a two-phase system, demonstrating the ability to extract or transport the carbohydrate (18)(19)(20)(21)(22)(23)(24). This latter approach is directly relevant to the transport of carbohydrates across biological membranes. Boron-based systems have again proved quite effective (22-24). However, for those receptors operating through noncovalent interactions, success has been limited thus far. Positive results have been obtained with the less hydrophilic saccharides at high aqueous concentrations (18, 20), but not in general with the more hydrophilic substrates such as glucose. § Recently we described the tricyclic tetraester 1a (Fig. 1), a novel receptor that showed an exceptional affinity for n-octyl ␤-D-glucoside, remarkable ␤ vs. ␣ selectivity, and the unusual ability to dissolve solid glucose in CHCl 3 (25). Although we hoped to demonstrate the extraction of glucose ...

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Highly Substituted ter-Cyclopentanes as Receptors for Lipid A

Abstract: Supporting Information Available: Selected spectra for UV titration data, spectra, NMR titration of 2 into 14, and Skatchard analyses (PDF). This material is available free of charge via the Internet at http://pubs.acs.org.

Cited by 67 publications

References 23 publications

An Enantioselective Fluorescence Sensor for Glucose Based on a Cyclic Tetrapeptide Containing Two Boronic Acid Binding Sites

An Enantioselective Fluorescence Sensor for Glucose Based on a Cyclic Tetrapeptide Containing Two Boronic Acid Binding Sites

A Synthetic Lectin Analog for Biomimetic Disaccharide Recognition

Phase transfer of monosaccharides through noncovalent interactions: Selective extraction of glucose by a lipophilic cage receptor

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