Peptide amphipathy: a new strategy in design of potential insecticides.
A 30-residue peptide [YAA(KALA)6LAA] with an amphipathic helix repeat unit of Lys-Ala-Leu-Ala (KALA) was synthesized as both the L- and the D-isomer. The peptide was shown to form alpha-helices and lyse lipid vesicles in a pH dependent fashion. The calculated helical amphipathic moment is +1.19 kcal/residue and the mean residue hydrophobicity is +0.4 kcal/residue. The formation of alpha-helices as the pH is increased is similar to poly-lysine, yielding a pK 10.2. Though not toxic when fed to insects, KALA killed Spodoptera frugiperda cells at low doses and Manduca sexta larvae when injected.
Frohlich
D R
DR
Department of Biochemistry, University of Arizona, Tucson.
Wells
M A
MA
D000595:Amino Acid Sequence; D000818:Animals; D015195:Drug Design; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000138:chemical synthesis*; D007814:Larva; D008969:Molecular Sequence Data; D009036:Moths; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation
D007306:Insecticides; D010455:Peptides