3150-25-2Relevant articles and documents
Strong Inhibition of Cholera Toxin B Subunit by Affordable, Polymer-Based Multivalent Inhibitors
Haksar, Diksha,De Poel, Eyleen,Van Ufford, Linda Quarles,Bhatia, Sumati,Haag, Rainer,Beekman, Jeffrey,Pieters, Roland J.
, p. 785 - 792 (2019/02/05)
Cholera is a potentially fatal bacterial infection that affects a large number of people in developing countries. It is caused by the cholera toxin (CT), an AB5 toxin secreted by Vibrio cholera. The toxin comprises a toxic A-subunit and a pentameric B-subunit that bind to the intestinal cell surface. Several monovalent and multivalent inhibitors of the toxin have been synthesized but are too complicated and expensive for practical use in developing countries. Meta-nitrophenyl α-galactoside (MNPG) is a known promising ligand for CT, and here mono- and multivalent compounds based on MNPG were synthesized. We present the synthesis of MNPG in greatly improved yields and its use while linked to a multivalent scaffold. We used economical polymers as multivalent scaffolds, namely, polyacrylamide, dextran, and hyperbranched polyglycerols (hPGs). Copper-catalyzed alkyne azide cycloaddition reaction (CuAAC) produced the inhibitors that were tested in an ELISA-type assay and an intestinal organoid swelling inhibition assay. The inhibitory properties varied widely depending on the type of polymer, and the most potent conjugates showed IC50 values in the nanomolar range.
Development and optimization of a competitive binding assay for the galactophilic low affinity lectin LecA from: Pseudomonas aeruginosa
Joachim, Ines,Rikker, Sebastian,Hauck, Dirk,Ponader, Daniela,Boden, Sophia,Sommer, Roman,Hartmann, Laura,Titz, Alexander
, p. 7933 - 7948 (2016/08/30)
Infections with the Gram-negative bacterium Pseudomonas aeruginosa result in a high mortality among immunocompromised patients and those with cystic fibrosis. The pathogen can switch from planktonic life to biofilms, and thereby shields itself against antibiotic treatment and host immune defense to establish chronic infections. The bacterial protein LecA, a C-type lectin, is a virulence factor and an integral component for biofilm formation. Inhibition of LecA with its carbohydrate ligands results in reduced biofilm mass, a potential Achilles heel for treatment. Here, we report the development and optimization of a fluorescence polarization-based competitive binding assay with LecA for application in screening of potential inhibitors. As a consequence of the low affinity of d-galactose for LecA, the fluorescent ligand was optimized to reduce protein consumption in the assay. The assay was validated using a set of known inhibitors of LecA and IC50 values in good agreement with the known Kd values were obtained. Finally, we employed the optimized assay to screen sets of synthetic thio-galactosides and natural blood group antigens and report their structure-activity relationship. In addition, we evaluated a multivalent fluorescent assay probe for LecA and report its applicability in an inhibition assay.
Evaluating N-benzylgalactonoamidines as putative transition state analogs for β-galactoside hydrolysis
Fan, Qiu-Hua,Striegler, Susanne,Langston, Rebekah G.,Barnett, James D.
, p. 2792 - 2800 (2014/05/06)
Experimental evidence is provided for p-methylbenzyl-d-galactonoamidine to function as a true transition state analog for the enzymatic hydrolysis of aryl-β-d-galactopyranosides by β-galactosidase (A. oryzae). The compound exhibits inhibition constants in the low nanomolar concentration range (12-56 nM) for a selection of substrates. Along these lines, a streamlined synthetic method based on phase-transfer catalysis was optimized to afford the required variety of new aryl-β-d-galactopyranosides. Last, the stability of the galactonoamidines under the assay conditions was confirmed. This journal is the Partner Organisations 2014.
