Purification and characterization of a scorpion defensin, a 4kDa antibacterial peptide presenting structural similarities with insect defensins and scorpion toxins.
Insect defensins are a group of inducible small-sized antibacterial peptides with three intramolecular disulfide bridges. NMR studies have recently shown that they share striking structural similarities with scorpion toxins. We have investigated in a scorpion species, Leiurus quinquestriatus, the potential presence of antibacterial molecules and report the isolation and structural characterization of a novel insect defensin homologue, which we refer to as scorpion defensin. This peptide shows a remarkably high degree of sequence homology with a defensin recently characterized in a species belonging to the ancient insect order of the Odonata with which it defines a novel ancient subclass of defensins. The scorpion defensin has in common with the scorpion toxins a consensus sequence Cys-[...]-Cys-Xaa-Xaa-Xaa-Cys-[...]-Gly-Xaa-Cys-[...]-Cys-Xaa-Cys present in all scorpion toxins characterized so far.
Cociancich
S
S
Laboratoire de Biologie Générale, Bases Moléculaires de la Réponse Immunitaire des Insectes, UA CNRS 1490, Strasbourg, France.
Goyffon
M
M
Bontems
F
F
Bulet
P
P
Bouet
F
F
Menez
A
A
Hoffmann
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D023082:Defensins; D004926:Escherichia coli / Q000187:drug effects; D006458:Hemolymph / Q000737:chemistry; D016982:Micrococcus luteus / Q000187:drug effects; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012604:Scorpion Venoms / Q000737:chemistry* / Q000302:isolation & purification; D012605:Scorpions; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D001798:Blood Proteins; D023082:Defensins; D012604:Scorpion Venoms