title: Exploration of the Innate Immune System of Styela clava: Zn2+Binding Enhances the Antimicrobial Activity of the Tunicate Peptide Clavanin A.
abstract: Tunicates have been used as primitive models for understanding cell-mediated and humoral immunity. Clavanin A (ClavA) is one member of a family of antimicrobial peptides produced by the solitary tunicate Styela clava. In this work, we demonstrate that ClavA utilizes Zn2+ions to potentiate its antimicrobial activity not only by reducing the concentration at which the peptide inhibits the growth of bacteria but also by increasing the rate of killing. Membrane depolarization, β-galactosidase leakage, and potassium leakage assays indicate that ClavA is membrane active, forms small pores, but induces cell death by targeting an intracellular component. ClavA and ClavA-Zn2+added to Escherichia coli and imaged by confocal microscopy translocate across the cell membrane. E. coli mutants lacking the functional Zn2+import system are less susceptible to ClavA, suggesting that the synergistic activity between ClavA and Zn2+has a cytoplasmic target, which is further supported by its nucleolytic activity. Overall, these studies identify a remarkable new mechanism by which zinc contributes to the immune response in the tunicate S. clava.
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Juliano
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Scott
authors.initials: S
authors.lastname: Pierce
authors.affiliation: Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: deMayo
authors.affiliation: Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Marcy J
authors.initials: MJ
authors.lastname: Balunas
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Alfredo M
authors.identifier: 0000-0002-5560-4405
authors.initials: AM
authors.lastname: Angeles-Boza
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000138:chemical synthesis / Q000276:immunology* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D001692:Biological Transport; D001798:Blood Proteins / Q000096:biosynthesis / Q000138:chemical synthesis / Q000276:immunology* / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D004357:Drug Synergism; D004926:Escherichia coli / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression; D006434:Hemocytes / Q000737:chemistry / Q000276:immunology; D007107:Immune System; D008826:Microbial Sensitivity Tests; D011188:Potassium / Q000378:metabolism; D011485:Protein Binding; D060327:Solid-Phase Synthesis Techniques; D014561:Urochordata / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D001798:Blood Proteins; C106713:clavanin A; D001616:beta-Galactosidase; D015032:Zinc; D011188:Potassium