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ChemPlusChem May 2020A molecular cage consisting of two cyclic hexapeptides with an alternating sequence of (2S,4S)-4-aminoproline and 6-aminopicolinic acid subunits, covalently linked via...
A molecular cage consisting of two cyclic hexapeptides with an alternating sequence of (2S,4S)-4-aminoproline and 6-aminopicolinic acid subunits, covalently linked via three diglycolic acid subunits, interacts with a variety of inorganic anions in acetonitrile/water. In the respective complexes, the anion resides in a cavity between the two cyclopeptide rings where it interacts with six converging NH groups. The cage binds sulfate anions in acetonitrile/water, 2 : 1 (v/v) with a log K of 6.7, ca. 2.5 orders of magnitude stronger than an analogous bis(cyclopeptide) with only one linker whose sulfate affinity log K amounts to 4.3. The preorganization induced by the three linking units is thus beneficial for sulfate binding. In addition, these linkers cause the dissociation of the sulfate complex to have a substantial Gibbs free energy of activation ΔG of 68.9 kJ mol and they also seem to affect anion selectivity as illustrated by the different effects some anions produce on the H NMR spectra of the triply and singly-linked bis(cyclopeptides). Such anion binding cages represent promising scaffolds to mimic natural anion receptors such as the sulfate-binding protein.
Topics: Anions; Iodides; Kinetics; Magnetic Resonance Spectroscopy; Peptides, Cyclic; Sulfates; Thermodynamics; Water
PubMed: 32406613
DOI: 10.1002/cplu.202000255 -
Chemphyschem : a European Journal of... Jan 2023Modulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors...
Modulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors includes both a urea motif and a tetrazine motif. The synthetic sequence towards three receptors is detailed. Impacts of H-bond strength and linker length between urea and tetrazine on chloride complexation are studied. Binding properties of the chloride anion are examined in both the ground and excited states using a panel of analytical methods (NMR spectroscopy, mass spectrometry, UV/Visible spectroscopies, and fluorescence). A ranking of the receptors by complexation strength has been determined, allowing a better understanding of the structure-properties relationship on these compounds.
Topics: Urea; Chlorides; Hydrogen Bonding; Anions
PubMed: 36111796
DOI: 10.1002/cphc.202200524 -
Chemical Society Reviews Feb 2009Nature has devised highly efficient and selective ways of recognizing anionic substrates by using surprisingly few building blocks the most important of which are the... (Review)
Review
Nature has devised highly efficient and selective ways of recognizing anionic substrates by using surprisingly few building blocks the most important of which are the amino acids serine, tryptophane, and arginine in addition to NH groups along the protein backbone. Deliberate use of amino acids for the construction of abiotic anion receptors could lead to systems that mimic the anion coordinating properties of anion binding proteins. With this aim in mind several groups have focused their attention on the development of anion receptors containing amino acid building blocks and came up with remarkably efficient systems. This critical review summarizes the different approaches (174 references).
Topics: Amides; Amino Acids; Anions; Crystallography, X-Ray; Guanidine; Thiourea
PubMed: 19169467
DOI: 10.1039/b810531f -
Inorganic Chemistry Nov 2022The recognition and adsorption of silver ions (Ag) from industrial wastewater are necessary but still challenging. Herein, we constructed four Zn(II)-based coordination...
The recognition and adsorption of silver ions (Ag) from industrial wastewater are necessary but still challenging. Herein, we constructed four Zn(II)-based coordination polymers (CPs), namely, [Zn(btap)(NO)] (), [Zn(btap)(SO)(HO)] (), {[Zn(btap)(HO)]·(ClO)} (), and [Zn(btap)Cl] (), by using 3,5-bis(triazol-1-yl)pyridine (btap) with different anionic Zn(II) salts. The crystal structures of -, varying from one-dimensional beaded () and zigzag chain () to two-dimensional () and () typologies, were regulated by the coordination modes of btap and the counter-anions. The water stability, pH stability, thermostability, and luminescent properties of the CPs were investigated. The luminescence performances in a series of cations and anions were also explored. Considering the high density of chloride groups in the structure, showed luminescence sensing for Ag [ = 9188.45 M and a limit of detection (LOD) of 4.9 μM], as well as an excellent ability for Ag adsorption in aqueous solution (maximum adsorption capacity, 653.3 mg/g). Additionally, anti-interference experiments revealed that had excellent recognition and adsorption capacities for Ag even when multiple ions coexisted. Moreover, XRD, EDS, and XPS analyses confirmed that the coordination of Ag with chloride groups in resulted in excellent adsorption capacity and prevented ligand-to-ligand electron transfer, showing excellent detection ability. Suitable coordination sites were introduced to interact strongly with Ag, along with detection and large adsorption capacity. Our strategy can effectively design and develop multifunctional CP-based materials, which are applicable in removal processes and environmental protection, by regulating anions in the self-assembly and introducing CP functional groups.
Topics: Silver; Polymers; Ligands; Adsorption; Chlorides; Anions; Water
PubMed: 36315939
DOI: 10.1021/acs.inorgchem.2c02355 -
Biochemistry Jul 2015We co-crystallized human cytochrome P450 3A4 (CYP3A4) with progesterone (PRG) under two different conditions, but the resulting complexes contained only one PRG molecule...
We co-crystallized human cytochrome P450 3A4 (CYP3A4) with progesterone (PRG) under two different conditions, but the resulting complexes contained only one PRG molecule bound to the previously identified peripheral site. A novel feature in one of our structures is a citrate ion, originating from the crystallization solution. The citrate-binding site is located in an area where the N-terminus splits from the protein core and, thus, is suitable for the interaction with the anionic phospholipids of the microsomal membrane. We investigated how citrate affects the function of a soluble CYP3A4 monooxygenase system consisting of equimolar amounts of CYP3A4 and cytochrome P450 reductase (CPR). Citrate was found to affect the properties of both redox partners and stimulated their catalytic activities in a concentration-dependent manner via a complex mechanism. CYP3A4-substrate binding, reduction of CPR with NADPH, and interflavin and interprotein electron transfer were identified as citrate-sensitive steps. Comparative analysis of various negatively charged organic compounds indicated that, in addition to alterations caused by changes in ionic strength, anions modulate the properties of CYP3A4 and CPR through specific anion-protein interactions. Our results help to better understand previous observations and provide new mechanistic insights into CYP3A4 function.
Topics: Anions; Binding Sites; Citrates; Crystallography, X-Ray; Cytochrome P-450 CYP3A; Enzyme Activation; Humans; Models, Molecular; Oxidation-Reduction; Progesterone
PubMed: 26066995
DOI: 10.1021/acs.biochem.5b00510 -
Pflugers Archiv : European Journal of... Feb 2004The organic anion transporting polypeptides (rodents: Oatps, human: OATPs) form a superfamily of sodium-independent transport systems that mediate the transmembrane... (Review)
Review
Organic anion transporting polypeptides of the OATP/ SLC21 family: phylogenetic classification as OATP/ SLCO superfamily, new nomenclature and molecular/functional properties.
The organic anion transporting polypeptides (rodents: Oatps, human: OATPs) form a superfamily of sodium-independent transport systems that mediate the transmembrane transport of a wide range of amphipathic endogenous and exogenous organic compounds. Since the traditional SLC21 gene classification does not permit an unequivocal and species-independent identification of genes and gene products, all Oatps/OATPs are newly classified within the OATP/ SLCO superfamily and subdivided into families (>/=40% amino acid sequence identity), subfamilies (>/=60% amino acid sequence identity) and individual genes and gene products according to their phylogenetic relationships and chronology of identification. Implementation of this new classification and nomenclature system occurs in agreement with the HUGO Gene Nomenclature Committee (HGNC). Among 52 members of the OATP/ SLCO superfamily, 36 members have been identified so far in humans, rat and mouse. The latter are clustered within 6 (out of 12) families (OATP1-OATP6) and 13 subfamilies. Oatps/OATPs represent 12 transmembrane domain proteins and contain the superfamily signature D-X-RW-(I,V)-GAWW-X-G-(F,L)-L. Although species divergence, multispecificity and wide tissue distribution are common characteristics of many Oatps/OATPs, some members of the OATP/ SLCO superfamily are highly conserved during evolution, have a high substrate specificity and exhibit unique cellular expression in distinct organs. Hence, while Oatps/OATPs with broad substrate specificity appear to play an important role in the bioavailability, distribution and excretion of numerous exogenous amphipathic organic anionic compounds, Oatps/OATPs with a narrow spectrum of transport substrates may exhibit more specific physiological functions in distinct organs.
Topics: Animals; Anions; Biological Transport; Humans; Multigene Family; Organic Anion Transporters; Phylogeny; Terminology as Topic
PubMed: 14579113
DOI: 10.1007/s00424-003-1168-y -
Chemical Communications (Cambridge,... Sep 2012The development of new optical anion chemosensors with high sensitivity and selectivity is very important, since anions possess some fundamental roles in a wide range of... (Review)
Review
The development of new optical anion chemosensors with high sensitivity and selectivity is very important, since anions possess some fundamental roles in a wide range of biological and chemical processes. The displacement approach is a method using anion binding sites and signaling subunits, which are not covalently attached but forming a coordination complex, in which the presence of anions revives the noncoordinated spectroscopic behavior of the indicator. In the past five years, according to the displacement strategy, many good optical anion chemosensors have been successfully obtained. This paper reviews the recent progress in the field of the fluorescent and colorimetric anion chemosensors designed according to the displacement strategy (mainly from 2008 to 2011), and gives some outlooks for the further exploration of new optical anion chemosensors.
Topics: Anions; Coordination Complexes; Cyanides; Diphosphates; Fluorescent Dyes; Metal Nanoparticles; Metals; Spectrometry, Fluorescence; Sulfides
PubMed: 22781135
DOI: 10.1039/c2cc33158f -
Journal of Colloid and Interface Science Jun 2022Despite the much progress in developing π-conjugated fluoroarene moieties based functional materials in which anion - π interactions are commonly involved, it...
Despite the much progress in developing π-conjugated fluoroarene moieties based functional materials in which anion - π interactions are commonly involved, it remains challenging to quantitatively characterize the nanomechanical interaction mechanism of these anion - π systems, particularly in aqueous solutions. In this study, we reported the first experimental quantification of the nanomechanics of anion - π interactions between π-conjugated fluoroarene moieties and carboxylate anions in aqueous solutions through direct molecular force measurements, with a special focus on the impact of the anion species, concentration and of the substitution effect of aromatic side group. The results using surface forces apparatus (SFA) and single-molecule force spectroscopy (SMFS) provide complementary evidences to demonstrate that the robust and reversible adhesion measured between the fluoroarene π systems and carboxylate anions was mainly attributed to anion - π interaction. Moreover, their nanomechanical properties were also systematically scrutinized, with the interaction strength being found to be significantly determined by the contact time, the type of fluoroarene systems (PFST > DFST) and the type of anions and ion concentration (HPO > CO > I > Cl ≈ NO > F).
Topics: Anions; Molecular Dynamics Simulation; Physical Phenomena; Water
PubMed: 35176544
DOI: 10.1016/j.jcis.2022.01.184 -
Molecules (Basel, Switzerland) Dec 2020A calix-shaped polyoxometalate, [VO] (), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of...
A calix-shaped polyoxometalate, [VO] (), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of an anion. The highly-reactive cyanate is smoothly trapped by to form [VO(CN)]. In the CHNO solution, cyanate abstracts protons from CHNO, and the resultant CHNO is stabilized in to form [VO(CHNO)] (). A crystallographic analysis revealed the double-bond characteristic short bond distance of 1.248 Å between the carbon and nitrogen atoms in the nitromethane anion in . H and C NMR studies showed that the nitromethane anion in must not be exchanged with the nitromethane solvent. Thus, the container restrains the reactivity of anionic species.
Topics: Anions; Calixarenes; Inorganic Chemicals; Methane; Models, Molecular; Molecular Structure; Nitroparaffins; Solvents
PubMed: 33271966
DOI: 10.3390/molecules25235670 -
Chemical Communications (Cambridge,... Aug 2022Two porphyrinic silver-chalcogenide cluster-based MOFs were achieved using a phosphate anionic template strategy, and the highly photoactive organic building modules...
Two porphyrinic silver-chalcogenide cluster-based MOFs were achieved using a phosphate anionic template strategy, and the highly photoactive organic building modules combined with Lewis acidic silver clusters allow both SCC-MOFs to be used as versatile catalysts for the simultaneous degradation of sulfur mustard and nerve agent simulants.
Topics: Anions; Chemical Warfare Agents; Metal-Organic Frameworks; Phosphates; Silver
PubMed: 35971910
DOI: 10.1039/d2cc03120e