title: Antimicrobial effects of H4-(86-100), histogranin and related compounds--possible involvement of DNA gyrase.
abstract: Histone-derived antimicrobial peptides have been identified in various organisms from plants to humans. The rat histone H4 mRNA variants, H4-v.1 and rat histogranin (HNr) mRNAs, were recently reported to be involved in the synthesis of H4-(86-100) and its related peptide HNr, respectively. Herein, the two peptides were investigated for putative antimicrobial activity and found to inhibit growth of gram-negative (Escherichia coli, Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis, Staphylococcus aureus) bacteria. Their inhibitory potencies in E. coli (LD(50): 3.48 and 4.34 microg x mL(-1)) are comparable to that of the antimicrobial peptide LL-37 (LD(50): 4.10 microg x mL(-1)). The antimicrobial activities of H4-(86-100) and HNr depend upon the integrity of the molecules, as precursors [H4-(84-102), pro-HNr] and fragments [bovine histogranin (HNb)-(1-13), HNb-(3-13), H4-(89-102) or OGP] are at least five times less potent than the parent peptides. Among various HN-like compounds, cyclo-(-Gly-pCl-Phe-Tyr-D-Arg) (compound 3) and N-5-guanidino pentanamide-(2R)-yl-2-N-(p-hydroxyphenylacetyl)-4-(p-chlorobenzoyl)-phenylene diamine (compound 8) display antimicrobial activities comparable to that of HNr. Interestingly, the antimicrobial activities of H4-(86-100), HNr and compound 3, like those of quinolone antibiotics acting as DNA gyrase poisons, are potentiated by ATP (1 mM) and coumermycin A1 (a DNA gyrase-linked ATPase inhibitor) and blocked by 2,4-dinitrophenol (DNP, an uncoupler of oxidative phosphorylation) and fluoroacetic acid (a metabolic poison). Finally, in vitro experiments indicate that H4-(86-100), HNr, compound 3 and compound 8, but not HNb-(1-13) or HNb-(3-13), inhibit DNA gyrase-mediated supercoiling of pBR322 DNA. These data indicate that the naturally occurring H4-(86-100) and HNr display antimicrobial effects that involve a modulation of ATP-dependent DNA gyrase.
authors.affiliation: Department of Molecular and Cellular Medicine, University of Ottawa, Canada. slemaire@uottawa.ca
authors.forename: Simon
authors.initials: S
authors.lastname: Lemaire
authors.forename: Thuy-Tiên
authors.initials: TT
authors.lastname: Trinh
authors.forename: Hoang-Thanh
authors.initials: HT
authors.lastname: Le
authors.forename: Shun-Chii
authors.initials: SC
authors.lastname: Tang
authors.forename: Maxwell
authors.initials: M
authors.lastname: Hincke
authors.forename: Olivier
authors.initials: O
authors.lastname: Wellman-Labadie
authors.forename: Sophie
authors.initials: S
authors.lastname: Ziai
mesh_terms: D000255:Adenosine Triphosphate; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D027081:DNA Gyrase / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006657:Histones / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011506:Proteins / Q000494:pharmacology; D051381:Rats
chemical_list: D000900:Anti-Bacterial Agents; D006657:Histones; D010446:Peptide Fragments; D011506:Proteins; C082312:histogranin; D000255:Adenosine Triphosphate; D027081:DNA Gyrase