The identification of a novel Sulfolobus islandicus CAMP‑like peptide points to archaeal microorganisms as cell factories for the production of antimicrobial molecules
Journal article, 2015
Background: Pathogenic bacteria easily develop resistance to conventional antibiotics so that even relatively new
molecules are quickly losing efficacy. This strongly encourages the quest of new antimicrobials especially for the
treatment of chronic infections. Cationic antimicrobial peptides (CAMPs) are small positively charged peptides with an
amphipathic structure, active against Gram-positive and Gram-negative bacteria, fungi, as well as protozoa.
Results: A novel (CAMP)-like peptide (VLL-28) was identified in the primary structure of a transcription factor, Stf76,
encoded by pSSVx, a hybrid plasmid–virus from the archaeon Sulfolobus islandicus. VLL-28 displays chemical, physical
and functional properties typical of CAMPs. Indeed, it has a broad-spectrum antibacterial activity and acquires a
defined structure in the presence of membrane mimetics. Furthermore, it exhibits selective leakage and fusogenic
capability on vesicles with a lipid composition similar to that of bacterial membranes. VLL-28 localizes not only on the
cell membrane but also in the cytoplasm of Escherichia coli and retains the ability to bind nucleic acids. These findings
suggest that this CAMP-like peptide could exert its antimicrobial activity both on membrane and intra cellular targets.
Conclusions: VLL-28 is the first CAMP-like peptide identified in the archaeal kingdom, thus pointing to archaeal
microorganisms as cell factories to produce antimicrobial molecules of biotechnological interest. Furthermore, results
from this work show that DNA/RNA-binding proteins could be used as sources of CAMPs.