Maximins S, a novel group of antimicrobial peptides from toad Bombina maxima.
Amphibian skin secretions are rich in antimicrobial peptides acting as important components of innate defense system against invading microorganisms. A novel type of peptide, designated as maximin S, was deduced by random sequencing of 793 clones from a constructed Bombina maxima skin cDNA library. The putative primary structures of maximin S peptides can be grouped into five species, in which maximin S1 has 14 amino acid residues and the rest of maximin S peptides (S2-S5) all have 18 amino acid residues. Unlike most of the amphibian antimicrobial peptides so far identified, the newly characterized four maximin S precursors are composed of maximin S1 and different combinations of tandem repeated maximin S2-S5 linked by internal peptides. Except maximin S1, the predicted secondary structures of maximin S2-S5 show a similar amphipathic alpha-helical structure. MALDI-TOF mass spectrometry analysis of partially isolated skin secretions of the toad indicates that most of the deduced maximin S peptides are expressed. Two deduced maximin S peptides (S1, S4) were synthesized and their antimicrobial activities were tested. Maximin S4 only had an antibiotic activity against mycoplasma and had no antibacterial or antifungal activity toward tested strains. Maximin S1 had no activity under the same conditions.
Wang
Ting
T
Department of Animal Toxinology, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
Zhang
Jie
J
Shen
Ji-Hong
JH
Jin
Yang
Y
Lee
Wen-Hui
WH
Zhang
Yun
Y
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001001:Anura; D001483:Base Sequence; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009174:Mycoplasma / Q000187:drug effects; D010455:Peptides; D012867:Skin / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000900:Anti-Bacterial Agents; D010455:Peptides