Invertebrate defensins are a family of cysteine-rich antimicrobial peptides,
primarily active against Gram-positive bacteria. These defensins have been
found in arthropods (insects, ticks, spiders and scorpions), in bivalve
molluscs and in a fungus. These peptides range in length from 32 to 51 amino
acids. There are six conserved cysteines all involved in intrachain disulfide
bonds. A schematic representation of peptides from the invertebrate defensin
family is shown below.
Plectasin from a saprophytic fungus (Pseudoplectania nigrella) .
We developed a profile that covers the whole structure of invertebrate
Although low level sequence similarities have been reported 
between the invertebrate defensins and mammalian defensins, the topological
arrangement of the disulfide bonds as well as the tertiary structure  are
completely different in the two families.
Because historically these defensins were first found in insects and
scorpions, they used to be called arthropod defensin family or insect
May 2008 / Pattern removed, profile added and text revised.
PROSITE method (with tools and information) covered by this documentation:
Lambert J. Keppi E. Dimarcq J.-L. Wicker C. Reichhart J.-M. Dunbar B. Lepage P. Van Dorsselaer A. Hoffmann J. Fothergill J.
Insect immunity: isolation from immune blood of the dipteran Phormia terranovae of two insect antibacterial peptides with sequence homology to rabbit lung macrophage bactericidal peptides.
Mygind P.H. Fischer R.L. Schnorr K.M. Hansen M.T. Sonksen C.P. Ludvigsen S. Raventos D. Buskov S. Christensen B. De Maria L. Taboureau O. Yaver D. Elvig-Jorgensen S.G. Sorensen M.V. Christensen B.E. Kjaerulff S. Frimodt-Moller N. Lehrer R.I. Zasloff M. Kristensen H.H.
Plectasin is a peptide antibiotic with therapeutic potential from a saprophytic fungus.
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