title: Systematic peptide engineering and structural characterization to search for the shortest antimicrobial peptide analogue of gaegurin 5.
abstract: As part of an effort to develop new, low molecular mass peptide antibiotics, we searched for the shortest bioactive analogue of gaegurin 5 (GGN5), a 24-residue antimicrobial peptide. Thirty-one kinds of GGN5 analogues were synthesized, and their biological activities were analyzed against diverse microorganisms and human erythrocytes. The structural properties of the peptides in various solutions were characterized by spectroscopic methods. The N-terminal 13 residues of GGN5 were identified as the minimal requirement for biological activity. The helical stability, the amphipathic property, and the hydrophobic N terminus were characterized as the important structural factors driving the activity. To develop shorter antibiotic peptides, amino acid substitutions in an inactive 11-residue analogue were examined. Single tryptophanyl substitutions at certain positions yielded some active 11-residue analogues. The most effective site for the substitution was the hydrophobic-hydrophilic interface in the amphipathic helical structure. At this position, tryptophan was the most useful amino acid conferring favorable activity to the peptide. The introduced tryptophan played an important anchoring role for the membrane interaction of the peptides. Finally, two 11-residue analogues of GGN5, which exhibited strong bactericidal activity with little hemolytic activity, were obtained as property-optimized candidates for new peptide antibiotic development. Altogether, the present approach not only characterized some important factors for the antimicrobial activity but also provided useful information about peptide engineering to search for potent lead molecules for new peptide antibiotic development.
authors.affiliation: National Research Laboratory for Membrane Protein Structure, College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors.forename: Hyung-Sik
authors.initials: HS
authors.lastname: Won
authors.forename: Seo-Jeong
authors.initials: SJ
authors.lastname: Jung
authors.forename: Hyung Eun
authors.initials: HE
authors.lastname: Kim
authors.forename: Min-Duk
authors.initials: MD
authors.lastname: Seo
authors.forename: Bong-Jin
authors.initials: BJ
authors.lastname: Lee
mesh_terms: D020106:Acrylamide / Q000494:pharmacology; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001419:Bacteria / Q000187:drug effects*; D001665:Binding Sites; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D004912:Erythrocytes / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D015202:Protein Engineering / Q000379:methods*; D011498:Protein Precursors / Q000737:chemistry; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D008823:Micelles; D010455:Peptides; D011498:Protein Precursors; C096397:gaegurin 5; D020106:Acrylamide; D014364:Tryptophan