A multi-laboratory benchmark study of isothermal titration calorimetry (ITC) using Ca2+ and Mg2+ binding to EDTA

Velázquez‐Campoy, Adrián; Claro, Bárbara; Abián, Olga; Höring, Jonas; Bourlon, Louis; Clavería-Gimeno, Rafael; Ennifar, Eric; England, Patrick; Chaires, Jonathan B.; Wu, Di; Piszczek, Grzegorz; Brautigam, Chad A.; Tso, Shih Chia; Zhao, Huaying; Schuck, Peter; Keller, Sandro; Bastos, Margarida

doi:10.1007/s00249-021-01523-7

Cited by 15 publications

(9 citation statements)

References 34 publications

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“…ITC is a conventional characterization method that uniquely measures binding reactions by detecting heat changes during the formation of complexes in various physicochemical processes. While ITC has been extensively reported in research involving metal ions and biomolecules [ 41 , 42 , 43 , 44 ], there are fewer reports concerning anions. The ITC data analysis software (v1.41) employs a non-linear regression, an iterative process where model variables are determined by making a series of approximations to the ITC titration curve.…”

Section: Resultsmentioning

confidence: 99%

Section: Reversibility and Reusability Of Probementioning

confidence: 99%

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A “Pincer” Type of Acridine–Triazole Fluorescent Dye for Iodine Detection by Both ‘Naked-Eye’ Colorimetric and Fluorometric Modes

Yu,

Jiang,

Mou

et al. 2024

Molecules

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Iodine, primarily in the form of iodide (I−), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions has been a significant challenge for decades due to interference from other anions. In this study, we designed and synthesized a new pincer-type acridine–triazole fluorescent probe (probe 1) with an acridine ring as a spacer and a triazole as a linking arm attached to two naphthol groups. This probe can selectively recognize iodide ions in a mixed solvent of THF/H2O (v/v, 9/1), changing its color from colorless to light yellow, making it suitable for highly sensitive and selective colorimetric and fluorescent detection in water systems. We also synthesized another molecular tweezer-type acridine–triazole fluorescent probe (probe 2) that exhibits uniform detection characteristics for iodide ions in the acetonitrile system. Interestingly, compared to probe 2, probe 1 can be detected by the naked eye due to its circulation effect, providing a simple method for iodine detection. The detection limit of probe 1 is determined to be 10−8 mol·L−1 by spectrometric titration and isothermal titration calorimetry measurements. The binding stoichiometry between probe 1 and iodide ions is calculated to be 1:1 by these methods, and the binding constant is 2 × 105 mol·L−1.

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Section: Resultsmentioning

confidence: 99%

Section: Reversibility and Reusability Of Probementioning

confidence: 99%

A “Pincer” Type of Acridine–Triazole Fluorescent Dye for Iodine Detection by Both ‘Naked-Eye’ Colorimetric and Fluorometric Modes

Yu,

Jiang,

Mou

et al. 2024

Molecules

View full text Add to dashboard Cite

show abstract

“…EDTA acted as a control as it is a strong chelator of Ca 2+ and Mg 2+ . 41 We performed a turbidimetric precipitation assay to qualitatively determine the amount of precipitation observed in the varied solutions. IP6 precipitated out of solution in the presence of low and high concentrations of CaCl2 and MgCl2 at pH's found in the small and large intestines.…”

Section: Characterization Of Ip6 Analog Binding To Divalent Cationsmentioning

confidence: 99%

Structure-activity relationship of inositol thiophosphate analogs as allosteric activators of Clostridioides difficile toxin B

Cummer,

Grosjean,

Bolteau

et al. 2024

Preprint

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Clostridioides difficile is a bacterium that causes life-threatening intestinal infections. Infection symptoms are mediated by a toxin secreted by the bacterium. Toxin pathogenesis is modulated by the intracellular molecule, inositol-hexakisphosphate (IP6). IP6 binds to a cysteine protease domain (CPD) on the toxin, inducing auto-proteolysis, which liberates a virulence factor in the cytosol. Here, we developped second-generation IP6 analogs designed to induce auto-proteolysis in the gut lumen, prior to toxin uptake, circumventing pathogenesis. We synthesized a panel of thiophosphate- and sulfate-containing IP6 analogs, and characterized their toxin binding affinity, auto-proteolysis induction as well as binding to physiological divalent cations. Our top candidate was soluble in physiological extracellular ion concentrations, unlike IP6. In addition, the IP6 analogs were more negatively charged than IP6, resulting in improved affinity and stabilization of the CPD, which enhanced toxin auto-proteolysis. Our data illustrate the optimization of IP6 with thiophosphate biomimetics which are more capable of inducing TcdB auto-proteolysis than the native ligand, warranting further studies in vivo.

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Section: Characterization Of Ip6 Analog Binding To Divalent Cationsmentioning

confidence: 99%

Structure-activity relationship of inositol thiophosphate analogs as allosteric activators of Clostridioides difficile toxin B

Cummer,

Grosjean,

Bolteau

et al. 2024

Preprint

View full text Add to dashboard Cite

Clostridioides difficile is a bacterium that causes life-threatening intestinal infections. Infection symptoms are mediated by a toxin secreted by the bacterium. Toxin pathogenesis is modulated by the intracellular molecule, inositol-hexakisphosphate (IP6). IP6 binds to a cysteine protease domain (CPD) on the toxin, inducing auto-proteolysis, which liberates a virulence factor in the cell cytosol. We developed second-generation IP6 analogs designed to induce auto-proteolysis in the gut lumen, prior to toxin uptake, circumventing pathogenesis. We synthesized a panel of thiophosphate-/sulfate-containing IP6 analogs, and characterized their toxin binding affinity, auto-proteolysis induction and cation interactions. Our top candidate was soluble in extracellular cation concentrations, unlike IP6. The IP6 analogs were more negatively charged than IP6, which improved affinity and stabilization of the CPD, enhancing toxin auto-proteolysis. Our data illustrate the optimization of IP6 with thiophosphate biomimetics which are more capable of inducing toxin auto-proteolysis than the native ligand, warranting further studies in vivo.

show abstract

A multi-laboratory benchmark study of isothermal titration calorimetry (ITC) using Ca2+ and Mg2+ binding to EDTA

Cited by 15 publications

References 34 publications

A “Pincer” Type of Acridine–Triazole Fluorescent Dye for Iodine Detection by Both ‘Naked-Eye’ Colorimetric and Fluorometric Modes

A “Pincer” Type of Acridine–Triazole Fluorescent Dye for Iodine Detection by Both ‘Naked-Eye’ Colorimetric and Fluorometric Modes

Structure-activity relationship of inositol thiophosphate analogs as allosteric activators of Clostridioides difficile toxin B

Structure-activity relationship of inositol thiophosphate analogs as allosteric activators of Clostridioides difficile toxin B

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