title: Genomic and functional characterization of three new venom peptides from the scorpion Heterometrus spinifer.
abstract: Three new cysteine-free venom peptides, which are referred to as Heterin-1, Heterin-2 and Spiniferin, respectively, were identified from the scorpion Heterometrus spinifer. Heterin-1, Heterin-2 and Spiniferin contain 43, 24 and 13 amino acid residues, respectively. Genomic analysis showed that the genomic organizations of the three peptides are consistent with those of the known Na(+), K(+) or Cl(-)-channel specific toxins from scorpions; this suggests that the genes of the cysteine-free and cysteine-rich peptides from scorpions were derived from a common ancestor. Antimicrobial assay demonstrated that Heterin-1 possesses potent activities against both Gram-positive and Gram-negative bacteria. Among the tested bacterial species, Heterin-1 is the most active against Bacillus megaterium and Micrococcus luteus with MICs of 4.0 μM and 4.0 μM, respectively. Heterin-2 is able to potently inhibit the growth of Gram-positive bacteria with MICs from 5.6 μM to 30.0 μM; however, it has weaker activities against the tested Gram-negative bacteria. It is interesting to see that deletion of the C-terminal random coiled tail (KKD) in Heterin-2 markedly changed the antimicrobial specificity and activity of the peptide. Spiniferin has very weak antimicrobial activities against both Gram-positive and Gram-negative bacteria. We found that introducing three net charges into the polar face of Spiniferin significantly increased its antimicrobial activity against the majority of the tested bacteria; however, in some instances, net charge on the polar face is not important for the antimicrobial activity of the peptide. These studies have expanded our understanding of the diversity, evolution and structure/function relationships of the cysteine-free peptides from scorpions.
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Shifen
authors.initials: S
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Nie
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China. Electronic address: xianchun.zeng@gmail.com.
authors.forename: Xian-Chun
authors.initials: XC
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Hanjun
authors.initials: H
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology & Department of Biological Science and Technology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China.
authors.forename: Yichen
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology; D002478:Cells, Cultured; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology; D016415:Sequence Alignment; D014688:Venoms / Q000737:chemistry*
chemical_list: D023181:Antimicrobial Cationic Peptides; D010455:Peptides; D014688:Venoms
keywords: Antimicrobial peptide; Cysteine-free peptide; Genomic organization; Heterometrus spinifer; Scorpion; Structure/function relationship