Probing the binding selected metal ions and biologically active substances to the antimicrobial peptide LL-37 using DSC, ITC measurements and calculations

• Published in: Journal of thermal analysis and calorimetry 2019-12, Vol.138 (6), p.4523-4529
• Main Authors: Makowska, Joanna, Wyrzykowski, Dariusz, Kamysz, Elżbieta, Tesmar, Aleksandra, Kamysz, Wojciech, Chmurzyński, Lech
• Format: Article
• Language: English
• Subjects: Acetylsalicylic acid; Analytical Chemistry; Antiinfectives and antibacterials; Ascorbic acid; Aspirin; Binding; Caffeine; Calorimetry; Chemistry; Chemistry and Materials Science; Copper; Differential scanning calorimetry; Ethylenediaminetetraacetic acid; Heat measurement; Inorganic Chemistry; Investigations; Mathematical analysis; Measurement Science and Instrumentation; Metal ions; Nickel; Peptides; Physical Chemistry; Polymer Sciences; Stoichiometry; Thermal stability; Titration calorimetry; Zinc compounds
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-019-08310-9

Differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) techniques have been used to describe physicochemical properties of polypeptide LL-37. LL-37 is a 37-residue, amphipathic, helical peptide, the only cathelicidin-derived antimicrobial peptide found in the human organism. Thermal stability of the LL-37 peptide in a water solution was measured by DSC over the 288.15–333.15 K range. Furthermore, the ITC method supported by theoretical calculations (peptide–ligand docking) were used to study the interactions between LL-37 and some divalent metal ions, namely Cu 2+ , Zn 2+ , and Ni 2+ ions as well as acetylsalicylic acid, ascorbic acid, and caffeine molecules. It has been proven that under experimental conditions, the LL-37 peptide reveals affinity only toward Cu 2+ and Zn 2+ ions. The stoichiometry, conditional binding constants, log K ITC , and thermodynamic parameters (∆ ITC G , ∆ ITC H , T ∆ ITC S ) of the resulting Cu(II) and Zn(II) complexes were determined and discussed.