title: A protein with antimicrobial activity in the skin of Schlegel's green tree frog Rhacophorus schlegelii (Rhacophoridae) identified as histone H2B.
abstract: An extract of the skin of Schlegel's green tree frog, Rhacophorus schlegelii (Anura: Rhacophoridae), contained a protein that inhibited the growth of the Gram-negative bacterium Escherichia coli but was inactive against the Gram-positive bacterium Staphylococcus aureus. The protein was purified to near homogeneity by reverse-phase HPLC and amino acid sequence analysis of the products of an endoproteinase Glu-C digest identified the protein as histone H2B. The complete primary structure of the 125 amino acid residue Rhacophorus histone H2B was determined by nucleotide sequence analysis of a cloned cDNA encoding the protein. Mass spectrometry demonstrated that the protein isolated from the skin was not post-translationally modified. Histone fragments with antimicrobial activity were not identified in the Rhacophorus skin extract nor were cationic, alpha-helical antimicrobial peptides of the kind isolated from the skins of several other frog families. The data provide further evidence that histones play a role in the defense against microorganisms.
authors.affiliation: Department of Biology, Faculty of Science, Toho University, Funabashi, 274-8510, Chiba, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Todd
authors.initials: T
authors.lastname: Isaacson
authors.forename: Shawichi
authors.initials: S
authors.lastname: Iwamuro
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents; D001001:Anura / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D006657:Histones / Q000737:chemistry* / Q000145:classification / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D017385:Sequence Homology; D012867:Skin / Q000737:chemistry* / Q000378:metabolism; D013045:Species Specificity; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D006657:Histones