Characterization of the unique function of a reduced amide bond in a cytolytic peptide that acts on phospholipid membranes.
The incorporation of a reduced amide bond, psi(CH(2)NH), into peptide results in an increase in the net positive charge and the perturbation of alpha-helical structure. By using this characteristic of the reduced amide bond, we designed and synthesized novel pseudopeptides containing reduced amide bonds, which had a great selectivity between bacterial and mammalian cells. A structure-activity relationship study on pseudopeptides indicated that the decrease in alpha-helicity and the increase in net positive charge in the backbone, caused by the incorporation of a reduced amide bond into the peptide, both contributed to an improvement in the selectivity between lipid membranes with various surface charges. However, activity results in vitro indicated that a perturbation of alpha-helical structure rather than an increase in net positive charge in the backbone is more important in the selectivity between bacterial and mammalian cells. The present result revealed that the backbone of membrane-active peptides were important not only in maintaining the secondary structure for the interactions with lipid membranes but also in direct interactions with lipid membranes. The present study showed the unique function of a reduced amide bond in cytolytic peptides and a direction for developing novel anti-bacterial agents from cytolytic peptides that act on the lipid membrane of micro-organisms.
Oh
J E
JE
Protein Chemistry Laboratory, Mogam Biotechnology Research Institute, 341 Pojung-Ri, Koosung-Myun, Yongin-City, Kyonggi-Do 449-910, South Korea.
Lee
K H
KH
D000577:Amides / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000166:cytology / Q000187:drug effects; D002176:Candida albicans / Q000166:cytology / Q000187:drug effects; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004396:Coloring Agents / Q000378:metabolism; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects; D005452:Fluoresceins / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008826:Microbial Sensitivity Tests; D009281:Naphthalenes / Q000378:metabolism; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D010743:Phospholipids / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011726:Pyridinium Compounds / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate / Q000378:metabolism; D055672:Static Electricity; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014270:Trifluoroethanol / Q000378:metabolism
D000577:Amides; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D004396:Coloring Agents; D005452:Fluoresceins; D008081:Liposomes; D009281:Naphthalenes; D010455:Peptides; D010743:Phospholipids; D011726:Pyridinium Compounds; C046466:N,N'-4-xylylenebis(pyridinium); D012967:Sodium Dodecyl Sulfate; D014270:Trifluoroethanol; C046465:8-amino-1,3,6-naphthalenetrisulfonic acid; C007740:fluorexon