Properties of surface-cross-linked micelles probed by fluorescence spectroscopy and their catalysis of phosphate ester hydrolysis

Chadha, Geetika; Zhao, Yan

doi:10.1016/j.jcis.2012.09.042

Cited by 26 publications

(16 citation statements)

References 46 publications

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“…[22] MINP, being a polycation, should do the same. [23] Since the acidic side chains of aspartic acid and glutamic acids have a p K a of ~4, they should be readily deprotonated near the surface of the MINP during the binding. This could be the possible reason for the lack of pH effect at 6–9 for the MINP binding.…”

Section: Resultsmentioning

confidence: 99%

Water‐Soluble Nanoparticle Receptors Supramolecularly Coded for Acidic Peptides

Zhao

2017

Chemistry A European J

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Sequence-specific recognition of peptides is of enormous importance to many chemical and biological applications, but has been difficult to achieve due to the minute differences in the side chains of amino acids. Acidic peptides are knownt op lay important roles in cell growth and gene expression. In this work, we report molecularly imprinted micelles coded with molecular recognition information for the acidic and hydrophobic side chains of acidic peptides. The imprinted receptors couldd istinguish acidic amino acids from other polar and nonpolar amino acids, with dissociation constants of tens of nanomolar for biologically active peptides containing up to 18 amino acids.

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Section: Resultsmentioning

confidence: 99%

Water‐Soluble Nanoparticle Receptors Supramolecularly Coded for Acidic Peptides

Zhao

2017

Chemistry A European J

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“…1-Anilinonaphthalene-8-sulphonate (ANS), af luorescent probe extensively used to track hydrophobic regionsi np roteins,w as employed to reveal the hydrophobicity of the aggregates. [21] A fluorescenceb lueshift is expected upon ANS binding, along with an increase in the fluorescence intensity,d ue to an increasei nt he rigidity of the probe within the hydrophobic pockets.Asc an be seen in Figure S22 (the Supporting Information), af luorescence emission band appearsa ta bout 460 nm in the spectrum of both compounds 2 and 4,b lueshifted from the weak emission of the blank solution at 490 nm. This band, which is more intense for compound 4 than for compound 2, corroborates the presence of hydrophobic regions.…”

Section: Mechanistic Studiesmentioning

confidence: 95%

Emergent Catalytic Behavior of Self‐Assembled Low Molecular Weight Peptide‐Based Aggregates and Hydrogels

Tena‐Solsona

Nanda

Díaz‐Oltra

et al. 2016

Chemistry A European J

122

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We report a series of short peptides possessing the sequence (FE)n or (EF)n and bearing l-proline at their N-terminus that self-assemble into high aspect ratio aggregates and hydrogels. We show that these aggregates are able to catalyze the aldol reaction, whereas non-aggregated analogues are catalytically inactive. We have undertaken an analysis of the results, considering the accessibility of catalytic sites, pKa value shifts, and the presence of hydrophobic pockets. We conclude that the presence of hydrophobic regions is indeed relevant for substrate solubilization, but that the active site accessibility is the key factor for the observed differences in reaction rates. The results presented here provide an example of the emergence of a new chemical property caused by self-assembly, and support the relevant role played by self-assembled peptides in prebiotic scenarios. In this sense, the reported systems can be seen as primitive aldolase I mimics, and have been successfully tested for the synthesis of simple carbohydrate precursors.

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“…The surfactant sodium dodecyl sulphate (SDS) forms one of the most interesting micellar scaffold, which efficiently improves heme-based catalysis [22,23]. The cross-linked micelle is another recent scaffold that appears as a reactive hydrophobic pocket for encapsulation of transition metal-based catalysts with a suitable ligation [27]. An anionic surfactant is not generally able to form a homogenous solution at low pH, but the addition of a cationic compound derives the micellization [28].…”

Section: Introductionmentioning

confidence: 99%

Metallo-vesicular catalysis: A mixture of vesicular cysteine/iron mediates oxidative pH switchable catalysis

Akbarzadeh

Moosavi-Movahedi

Shockravi

et al. 2016

Journal of Molecular Catalysis A: Chemical

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The design of heme and non-heme active centers, which resemble peroxidase enzymes, has recently received a significant attention. Herein, a cystein-metal complex was designed and encapsulated in a vesicular mixture (1:4; SDS/DTAB) in order to imitate a chloroperoxidase (CLP) enzyme via chlorination of thionine at pH 3. This artificial enzyme behaved both as a catalase and CLP at pH 3, and as a peroxidase at pH 1. The shape of the metallo-vesicular catalyst at each pH value was obtained by dynamic light scattering, and was confirmed by transmission electron microscopy (TEM). The different fluidities as interior structure property of catalyst aggregates at pH 3 and 1 were obtained by differential scanning calorimetry (DSC). IR, 1 H and 13 C NMR spectroscopies were utilized to investigate the structural properties of the vesicular catalyst. These studies demonstrated that the cysteine/iron (III) center acted as a multifunctional catalyst. In addition, the sulfur and ammonium moieties of L-Cys interacted in the presence of metal ion at pH 1. However, the ammonium side chain was replaced with the carboxylate group at pH 3. Collectively, we engineered two distinct vesicular cysteinate-Fe 3+/2+ complexes, which functioned as a pH-switchable catalyst.

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Properties of surface-cross-linked micelles probed by fluorescence spectroscopy and their catalysis of phosphate ester hydrolysis

Cited by 26 publications

References 46 publications

Water‐Soluble Nanoparticle Receptors Supramolecularly Coded for Acidic Peptides

Water‐Soluble Nanoparticle Receptors Supramolecularly Coded for Acidic Peptides

Emergent Catalytic Behavior of Self‐Assembled Low Molecular Weight Peptide‐Based Aggregates and Hydrogels

Metallo-vesicular catalysis: A mixture of vesicular cysteine/iron mediates oxidative pH switchable catalysis

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