Ndour Mbaye, Janot Jean-Marc, Soussan Laurence, Bouaziz Zaineb, Voiry Damien, Balme Sebastien
Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France.
Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France.
Colloids Surf B Biointerfaces. 2019 Nov 1;183:110419. doi: 10.1016/j.colsurfb.2019.110419. Epub 2019 Aug 2.
In this work, we investigated the impact of different polyelectrolytes (polyacrylic acid, polystyrene sulfonate, dextran sulfate, and chondroitin sulfate) on lysozyme properties when they form colloidal complexes. To this aim, we characterized (i) the size and stability of the different polyelectrolyte-lysozyme complexes upon addition of NaCl (different concentrations) by diffusion light scattering, and (ii) the structure and accessibility of lysozyme active site in such complexes by fluorescence quenching and time resolved fluorescence analysis. We then used these results to explain the antibacterial activity variations among colloidal complexes and compared with free lysozyme. Our findings show that colloidal complexes that are more prone to swelling (i.e., lysozyme complexed with polystyrene sulfonate) are less stable upon salt addition. In these colloids, the enzymatic site is also more accessible. However, the antibacterial activity does not depend on the swelling properties because no large structural modification of the active site occurs.
在这项工作中，我们研究了不同聚电解质（聚丙烯酸、聚苯乙烯磺酸盐、硫酸葡聚糖和硫酸软骨素）在形成胶体复合物时对溶菌酶性质的影响。为此，我们通过扩散光散射表征了（i）添加不同浓度NaCl后不同聚电解质-溶菌酶复合物的尺寸和稳定性，以及（ii）通过荧光猝灭和时间分辨荧光分析表征了此类复合物中溶菌酶活性位点的结构和可及性。然后，我们利用这些结果来解释胶体复合物之间抗菌活性的差异，并与游离溶菌酶进行比较。我们的研究结果表明，更易于膨胀的胶体复合物（即与聚苯乙烯磺酸盐复合的溶菌酶）在添加盐后稳定性较差。在这些胶体中，酶活性位点也更容易接近。然而，抗菌活性并不取决于膨胀性质，因为活性位点没有发生大的结构修饰。
