P. Fehlbaum et al., STRUCTURE-ACTIVITY ANALYSIS OF THANATIN, A 21-RESIDUE INDUCIBLE INSECT DEFENSE PEPTIDE WITH SEQUENCE HOMOLOGY TO FROG-SKIN ANTIMICROBIAL PEPTIDES, Proceedings of the National Academy of Sciences of the United Statesof America, 93(3), 1996, pp. 1221-1225
Immune challenge to the insect Podisus maculiventris induces synthesis
of a 21-residue peptide with sequence homology to Frog skin antimicro
bial peptides of the brevinin family, The insect and frog peptides hav
e in common a C-terminally located disulfide bridge delineating a cati
onic loop, The peptide is bactericidal and fungicidal, exhibiting the
largest antimicrobial spectrum observed so far for an insect defense p
eptide, An all-D-enantiomer is nearly inactive against Gram-negative b
acteria and some Gram-positive strains but is fully active against fun
gi and other Gram-positive bacteria, suggesting that more than one mec
hanism accounts for the antimicrobial activity of this peptide, Studie
s with truncated synthetic isoforms underline the role of the C-termin
al loop and flanking residues for the activity of this molecule for wh
ich we propose the name thanatin.