Design of novel analogue peptides with potent antibiotic activity based on the antimicrobial peptide, HP (2-20), derived from N-terminus of Helicobacter pylori ribosomal protein L1.
HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antimicrobial sequence derived from the N-terminus of Helicobacter pylori ribosomal protein L1 (RPL1). In order to develop novel antibiotic peptides useful as therapeutic agents, potent antibiotic activities against bacteria, fungi and cancer cells without a cytotoxic effect are essential. To this end, several analogues with amino acid substitutions were designed to increase or decrease only the net hydrophobicity. In particular, the substitution of Trp for the hydrophobic amino acids, Gln and Asp at positions 17 and 19 of HP (2-20) (Anal 3), caused a dramatic increase in antibiotic activity without a hemolytic effect. In contrast, the decrease of hydrophobicity brought about by substituting Ser for Leu and Phe at positions 12 and 19 of HP (2-20), respectively (Anal 4, Anal 5), did not have a significant effect on the antibiotic activity. The antibiotic effects of these synthetic peptides were further investigated by treating prepared protoplasts of Candida albicans and conducting an artificial liposomal vesicle (PC/PS; 3:1, w/w) disrupting activity test. The results demonstrated that the Anal 3 prevented the regeneration of fungal cell walls and induced an enhanced release of fluorescent dye (carboxyfluorescein) trapped in the artificial membrane vesicles to a greater degree than HP (2-20). The potassium-release test conducted on C. albicans indicated that Anal 3 induced greater amounts of potassium ion to be released than the parent peptide, HP (2-20) did. These results indicated that the hydrophobic region of peptides is prerequisite for its effective antibiotic activity and may facilitate easy penetration of the lipid bilayers of the cell membrane.
Lee
Dong Gun
DG
Research Center for Proteineous Materials, Chosun University, 375 Seosuk-Dong, Dong-Ku, Kwangju, South Korea.
Kim
Hee Nam
HN
Park
Yoonkyung
Y
Kim
Hyung Keun
HK
Choi
Bo Hwa
BH
Choi
Cheol-Hee
CH
Hahm
Kyung-Soo
KS
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000633:toxicity; D001412:Bacillus subtilis / Q000187:drug effects; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D015195:Drug Design; D004926:Escherichia coli / Q000187:drug effects; D016480:Helicobacter pylori / Q000737:chemistry*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification; D010455:Peptides / Q000138:chemical synthesis* / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D012269:Ribosomal Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D001426:Bacterial Proteins; C433783:Hp (2-20) protein, Helicobacter pylori; D010446:Peptide Fragments; D010455:Peptides; D012269:Ribosomal Proteins; C028546:ribosomal protein L1