Substitution of the arginine/leucine residues in apidaecin Ib with peptoid residues: effect on antimicrobial activity, cellular uptake, and proteolytic degradation.
Several aspects of the mechanism of action of Pro-rich antimicrobial peptides, together with their low toxicity in mammalian cells, make them good candidates for the development of new antibiotic agents. We investigated the effect induced in the insect antimicrobial peptide apidaecin Ib by the replacement of a single arginine/leucine residue with a N-substituted glycine. The resulting peptoid-peptide hybrids are more resistant to proteolysis and devoid of any significant cytotoxic activity, but moving the [NArg]residue from the N- to the C-terminal end of the molecule progressively reduces the antibacterial activity. Cell uptake experiments in E. coli cells suggest that the loss of antibacterial activity of [NArg(17)]apidaecin is a consequence of its inability to translocate into bacterial cells. Conversely, apidaecin and its peptoid-peptide hybrids are able to cross the plasma membrane in eukaryotic cells and to diffuse in the cytosol, although their translocating ability is far less effective than that of other known cell permeant peptides.
Gobbo
Marina
M
Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131 Padova, Italy. marina.gobbo@unipd.it
Benincasa
Monica
M
Bertoloni
Giulio
G
Biondi
Barbara
B
Dosselli
Ryan
R
Papini
Emanuele
E
Reddi
Elena
E
Rocchi
Raniero
R
Tavano
Regina
R
Gennaro
Renato
R
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D001120:Arginine / Q000737:chemistry*; D002463:Cell Membrane Permeability; D002942:Circular Dichroism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes; D006367:HeLa Cells; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D006868:Hydrolysis; D007711:Klebsiella pneumoniae / Q000187:drug effects; D007930:Leucine / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D034444:Peptoids / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D019779:Salmonella enterica / Q000187:drug effects; D012486:Salmonella typhimurium / Q000187:drug effects; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D005456:Fluorescent Dyes; D034444:Peptoids; C061361:apidaecin; D001120:Arginine; D007930:Leucine