Effect of amino acid substitution in amphiphilic alpha-helical peptides on peptide-phospholipid membrane interaction.
It was previously found that a cationic amphiphilic peptide, Ac-(Leu-Ala-Arg-Leu)3-NHCH3 (4(3)), caused the destabilization of a phospholipid membrane and showed strong antibacterial activity [Lee et al. Biochim. Biophys. Acta 1986; 862: 211-219]. In order to investigate the effect of changing alpha-helix propensity, hydrophobicity and basicity in 4(3) on the peptide conformation and activity, the 4(3) analogs, [Gly (or Val)6]4(3), [Gly (or Val)2,6]4(3), [Gly (or Val)2,6,10]4(3), [Gln3]4(3), [Gln3,7]4(3) and [Gln3,7,11]4(3) were synthesized. Except for [Val2,6]4(3) and [Val2,6,10]4(3), which mainly formed a beta-structure, other peptides formed an alpha-helix and showed moderate membrane-perturbing activity toward neutral and acidic lipid vesicles. All the peptides other than [Val2,6,10]4(3) and [Gln3,7,10]4(3) had the antibacterial activity comparable with that of 4(3). The relationship between the membrane-perturbing activity and the antibacterial activity was not always parallel. Conclusively, the Ala-->Val substitution in 4(3) causes the change of peptide conformation and the presence of a cationic amino acid residue is necessary for the antibacterial activity.
Niidome
T
T
Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Japan.
Anzai
S
S
Sonoda
J
J
Tokunaga
Y
Y
Nakahara
M
M
Hatakeyama
T
T
Aoyagi
H
H
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D002942:Circular Dichroism; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D008563:Membrane Lipids / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology; D010743:Phospholipids / Q000737:chemistry*; D011817:Rabbits
D000900:Anti-Bacterial Agents; D008563:Membrane Lipids; D009842:Oligopeptides; D010743:Phospholipids