The identification of a novel Sulfolobus islandicus CAMP-like peptide points to archaeal microorganisms as cell factories for the production of antimicrobial molecules.
BACKGROUND
Pathogenic bacteria easily develop resistance to c onventional 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.
Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy. notomist@unina.it.
Eugenio
E
Notomista
Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. annarita.falanga@unina.it.
Annarita
A
Falanga
Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy. salvatore.fusco@unina.it.
Salvatore
S
Fusco
Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. luciano.pirone@unina.it.|C.I.R.C.M.S.B. (Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici), via Celso Ulpiani, 27, 70125, Bari, Italy. luciano.pirone@unina.it.
Luciano
L
Pirone
Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy. anna.zanfardino@unina.it.
Anna
A
Zanfardino
Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. stefania.galdiero@unina.it.|Department of Pharmacy and CiRPEB, University of Naples Federico II, 80100, Naples, Italy. stefania.galdiero@unina.it.
Stefania
S
Galdiero
Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy. varcamon@unina.it.
Mario
M
Varcamonti
Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. empedone@unina.it.
Emilia
E
Pedone
Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy. contursi@unina.it.
Patrizia
P
Contursi
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis* / Q000494:pharmacology; D019843:Archaeal Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000242:Cyclic AMP / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D016944:Sulfolobus / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D019843:Archaeal Proteins; D000242:Cyclic AMP