******************************
* Insect defensins signature *
******************************

Insect defensins   are  a  family  of  cysteine-rich  antibacterial  peptides,
primarily active  against gram-positive bacteria. The peptides known to belong
to this family are listed below.

 - Phormicin A and B from black blowfly (Phormia terranovae) [1].
 - Royalisin from the royal jelly of honey bee [2].
 - Sapecin and sapecin C from flesh fly (Sarcophaga peregrina) [3].
 - Antibacterial peptides B and C from the beetle Zophobas atratus [4].
 - Defensin from the larva of the dragonfly Aeschna cyanea [5].

All  these  peptides range in length from 38 to 51 amino acids.  There are six
conserved cysteines all  involved  in intrachain disulfide bonds.  A schematic
representation of peptides from the insect defensin family is shown below.

            +----------------------------+
            |              **************|********
          xxCxxxxxxxxxxxxxxCxxxCxxxxxxxxxCxxxxxCxCxx
                           |   |               | |
                           +---|---------------+ |
                               +-----------------+

'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern.

-Consensus pattern: C-x(3)-C-x(3,4)-G-x(2)-G-G-x-C-x(1,4)-K-x(2)-C-x-C
                    [The five C's are involved in disulfide bonds]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Note: although  low  level  sequence  similarities  have  been  reported  [1]
 between insect defensins and mammalian defensins, the topological arrangement
 of the disulfide  bonds  as well as the tertiary structure [6] are completely
 different in the two families.

-Last update: October 1993 / Text revised.

[ 1] Lambert J., Keppi E., Dimarcq J.-L., Wicker C., Reichhart J.-M.,
     Dunbar B., Lepage P., van Dorsselaer A., Hoffmann J., Fothergill J.,
     Hoffmann D.
     Proc. Natl. Acad. Sci. U.S.A. 86:262-266(1989).
[ 2] Fujiwara S., Imai J., Fujiwara M., Yaeshima T., Kawashima T.,
     Kobayashi K.
     J. Biol. Chem. 265:11333-11337(1990).
[ 3] Yamada K., Natori S.
     Biochem. J. 291:275-279(1993).
[ 4] Bulet P., Cociancich S., Dimarcq J.-L., Lambert J., Reichhart J.-M.,
     Hoffmann D., Hetru C., Hoffmann J.A.
     J. Biol. Chem. 266:24520-24525(1991).
[ 5] Bulet P., Cociancich S., Reuland M., Sauber F., Bischoff R., Hegy G.,
     van Dorsselaer A., Hetru C., Hoffmann J.A.
     Eur. J. Biochem. 209:977-984(1992).
[ 6] Hanzawa H., Shimada I., Kuzuhara T., Komano H., Kohda D., Inagaki F.,
     Natori S., Arata Y.
     FEBS Lett. 269:413-420(1990).