Allosteric effects. Remote control of ion transport selectivity

Rebek, Julius; Wattley, R. V.

doi:10.1021/ja00534a058

Cited by 105 publications

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“…Due to the fact that binding of both cations-the transition metal ion and for example, an alkali or alkaline earth metal ion-can cause substantial conformational changes, the roles-effector and substratemight also be reversed in some of these receptors. [13,14] A similar approach was presented by Rodríguez-Ubis and Brunet and co-workers who described a strong negatively cooperative allosteric effect in the transport of diammonium ions by receptor 25 in the presence or absence of ZnI 2 as the effector (Scheme 20). The use of 2,2'-bipyridines or similar chelating ligands that undergo significant conformational changes upon coordination to (transition) metal ion as a molecular hinge (or allosteric center) [60] can also be used to achieve heterotropic negatively cooperative binding as already demonstrated by the pioneering work of Rebek, Jr. depicted in Scheme 1.…”

Section: Heterotropic Positively Cooperative Binding Of Other Cationsmentioning

confidence: 81%

“…[13][14][15] These showed negative cooperative binding of alkali metal ions in the presence of suitable transition metal salts or complex fragments (HgCl 2 , ZnCl 2 , PdCl 2 , or Abstract: Cooperative effects in the binding of two or more substrates to different binding sites of a receptor that are a result of a conformational change caused by the binding of the first substrate-also referred to as the effector-are called allosteric effects. Probably the earliest work in this field came from Rebek, Jr. in the late 1970s/early 1980s when he described heterotropic systems based on crown ethers containing a 3,3'-disubstitued 2,2'-bipyridine unit (1, Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

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Artificial Allosteric Receptors

Kremer¹,

Lützen²

2013

Chemistry A European J

132

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Cooperative effects in the binding of two or more substrates to different binding sites of a receptor that are a result of a conformational change caused by the binding of the first substrate--also referred to as the effector--are called allosteric effects. In biological systems, allosteric regulation is a widely used mechanism to control the function of proteins and enzymes in cellular metabolism. Inspired by this a lot of efforts have been made in supramolecular chemistry to implement this concept into artificial systems to control functions as molecular recognition, signal amplification, or even reactivity and catalysis. This review gives an up-to-date overview over the different approaches that have been reported ever since the first examples from the late 1970s/early 1980s. It covers both homo- and heterotropic examples and is divided according to the nature of the effector--cationic, anionic, or neutral--effectors and systems that use combinations of those.

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Section: Heterotropic Positively Cooperative Binding Of Other Cationsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Artificial Allosteric Receptors

Kremer¹,

Lützen²

2013

Chemistry A European J

132

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“…Over the years, a large number of artificial receptors displaying positive (5)(6)(7)(8) and negative (9)(10)(11) homotropic and positive (12)(13)(14)(15)(16)(17)(18)(19)(20) and negative (21)(22)(23) heterotropic cooperative binding phenomena have been developed. Although in many cases the origins of the cooperative effects could be identified, few studies have dealt in detail with the kinetics and thermodynamics of such complicated multicomponent receptor-guest systems.…”

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confidence: 99%

Squaring cooperative binding circles

Deutman

Monnereau

Moalin

et al. 2009

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

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The cooperative binding effects of viologens and pyridines to a synthetic bivalent porphyrin receptor are used as a model system to study how the magnitudes of these effects relate to the experimentally obtained values. The full thermodynamic and kinetic circles concerning both activation and inhibition of the cage of the receptor for the binding of viologens were measured and evaluated. The results strongly emphasize the apparent character of measured binding and rate constants, in which the fractional saturation of receptors with other guests is linearly expressed in these constants. The presented method can be used as a simple tool to better analyze and comprehend the experimentally observed kinetics and thermodynamics of natural and artificial cooperative systems.kinetics ͉ slippage ͉ supramolecular chemistry ͉ thermodynamics C ooperative binding plays an important role in nature, where it is used to construct well-defined assemblies and is used as a tool to transfer information at the cellular level (1). The formation of the tobacco mosaic virus (2) and the binding of oxygen to hemoglobin (3) are 2 well-known examples of cooperative processes. Cooperative binding interactions can be homotropic or heterotropic, when the combined binding to a multivalent receptor involves the same or different types of guests. In additions, these interactions can be positive or negative, when the binding of a guest promotes or obstructs the binding of a second guest (4).One of the challenges in the field of supramolecular chemistry is to design artificial systems that display cooperative binding effects, not only to better understand the mechanisms involved in the natural processes but also to prepare functional materials and catalysts that benefit from such binding interactions. Over the years, a large number of artificial receptors displaying positive (5-8) and negative (9-11) homotropic and positive (12-20) and negative (21-23) heterotropic cooperative binding phenomena have been developed. Although in many cases the origins of the cooperative effects could be identified, few studies have dealt in detail with the kinetics and thermodynamics of such complicated multicomponent receptor-guest systems. This is surprising, because unlike the complex biological systems, the artificial receptor-guest systems can be easily studied, and the fine details of cooperative behavior can be uncovered. It is generally known that measured association constants are context dependent in the sense that apparent values that depend on, e.g., the solvent system, salt concentrations, pH, and in the worst case impurities, are obtained (4). As a consequence, the observed cooperative binding effects might often deviate from the intrinsic ones.To investigate how the measured cooperative binding effects as derived from the observed experimental binding constants are related to the intrinsic ones, we present a detailed study of the combined binding of viologens and pyridines to the bivalent zinc porphyrin receptor Zn1 (24, 25) (Scheme 1). Pyridine ligan...

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“…These are important aspects in the development of functional molecular devices of increasing complexity. 12 Pioneering contributions by Rebek et al in the early 1980s [13][14][15] describe a system involves a 2,2 0 -bipyridyl function attached at the 3,3…”

Section: Introductionmentioning

confidence: 99%

“…Ultimately, the activity is switched ''on'' or ''off. '' In this account, a further processing on the classic and simplest example of an allosteric molecular switch, which was described by Rebek et al [13][14][15] had been studied by theoretical method.…”

Section: Introductionmentioning

confidence: 99%

Density functional theory study of a molecular allosteric switch for 2,2′‐bipyridyl‐3,3′‐15‐crown‐5

et al. 2010

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A classical model of "molecular machine," which acts as an ON-OFF switch for 2,2'-bipyridyl-3,3'-15-crown-5 (L), has been theoretically studied. It is highly important to understand the mechanism of this switch. The alkali-metal cations (Na(+) and K(+) ) and W(CO)(4) fragment are introduced to coordinate with the different active sites of L, respectively. The density functional theory (DFT) method is used for understanding the stereochemical structural natures and thermodynamic properties of all the target molecules at B3LYP/6-31G(d) and SDD (Stuttgart-Dresden) level, together with the corresponding effective core potential (ECP) for tungsten (W). The fully optimized geometries have been performed with real frequencies, which indicate the minima states. The nucleophilicity of L has been investigated by the Fukui functions. The natural bond orbital analysis is used to study the intermolecular charge-transfer interactions and explore the origin of the internal forces of the molecular switch. In addition, the binding energies, enthalpies, Gibbs free energies, and the cation exchange energies have been studied for L, W(CO)(4) L, and their corresponding complexes. The properties of the complexes displayed by in presence or absence of the W(CO)(4) fragment are also analyzed. The calculated results of allosterism displayed by L are in a good agreement with the experimental results.

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Allosteric effects. Remote control of ion transport selectivity

Cited by 105 publications

References 0 publications

Artificial Allosteric Receptors

Artificial Allosteric Receptors

Squaring cooperative binding circles

Density functional theory study of a molecular allosteric switch for 2,2′‐bipyridyl‐3,3′‐15‐crown‐5

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