Hello,
I have a problem. My recombinant producted LL-37 form only alfa helix (CD spec.) and doesnt have antibacterial activity. Synthetic peptid LL-37 form random-coil (i see on CD spec.) and have antibacterial activity. Have you encountered anyone with this problem? How I transform alfa-helix to random-coil?
Thank you for answer,
Mr. Antonin Pavelka
Dear Antonín Pavelka ,
You most likely are familiar with this paper:
Article Conformation-dependent antibacterial activity of the natural...
It states and I quote: “At micromolar concentration in water, LL-37 exhibits a circular dichroism spectrum consistent with a disordered structure. The addition of 15 mm HCO3−, SO42−, or CF3CO2− causes the peptide to adopt a helical structure, with approximately equal efficiency, while 160 mm Cl− is less efficient.” And “A cooperative transition from disordered to helical structure is observed as the peptide concentration is increased, consistent with formation of an oligomer.”
In other words (as also done in this paper), preferably your peptide should be dissolved in pure water (since ions can cause conformation changes and change the extend of oligomer formation). To achieve this, you might try to freeze-dry your recombinant peptide or preferably try dialysis (https://www.thermofisher.com/nl/en/home/life-science/protein-biology/protein-biology-learning-center/protein-biology-resource-library/pierce-protein-methods/dialysis-methods-protein-research.html).
Best regards.
I already have both of peptides in water, I will try add urea range 0 to 8M....maybe urea denature recombinant peptide LL-37. Because I producted LL-37 in fusion with ubiquitin (maybe this protein induct folding of peptide). Thank you I will look at this article, that you recommend.
Best regards.