Antibacterial activity of peptides derived from the C-terminal region of a hemolytic lectin, CEL-III, from the marine invertebrate Cucumaria echinata.
Several synthetic peptides derived from the C-terminal domain sequence of a hemolytic lectin, CEL-III, were examined as to their action on bacteria and artificial lipid membranes. Peptide P332 (KGVIFAKASVSVKVTASLSK-NH(2)), corresponding to the sequence from residue 332, exhibited strong antibacterial activity toward Gram-positive bacteria. Replacement of each Lys in P332 by Ala markedly decreased the activity. However, when all Lys were replaced by Arg, the antibacterial activity increased, indicating the importance of positively charged residues at these positions. Replacement of Val by Leu also led to higher antibacterial activity, especially toward Gram-negative bacteria. The antibacterial activity of these peptides was correlated with their membrane-permeabilizing activity toward the bacterial inner membrane and artificial lipid vesicles, indicating that the antibacterial action is due to perturbation of bacterial cell membranes, leading to enhancement of their permeability. These results also suggest that the hydrophobic region of CEL-III, from which P332 and its analogs were derived, may play some role in the interaction with target cell membranes to trigger hemolysis.
Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Nagasaki 852-8521. thata@net.nagasaki-u.ac.jp
Tomomitsu
T
Hatakeyama
Tomoko
T
Suenaga
Seiichiro
S
Eto
Takuro
T
Niidome
Haruhiko
H
Aoyagi
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D048016:Cucumaria; D037102:Lectins / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; C402644:CEL-III lectin, Cucumaria echinata; D037102:Lectins; D010446:Peptide Fragments