title: In vitro system for high-throughput screening of random peptide libraries for antimicrobial peptides that recognize bacterial membranes.
abstract: Antibacterial peptides have been isolated from a wide range of species. Some of these peptides act on microbial membranes, disrupting their barrier function. With the increasing development of antibiotic resistance by bacteria, these antibacterial peptides, which have a new mode of action, have attracted interest as antibacterial agents. To date, however, few effective high-throughput approaches have been developed for designing and screening peptides that act selectively on microbial membranes. In vitro display techniques are powerful tools to select biologically functional peptides from peptide libraries. Here, we used the ribosome display system to form peptide-ribosome-mRNA complexes in vitro from nucleotides encoding a peptide library, as well as immobilized model membranes, to select specific sequences that recognize bacterial membranes. This combination of ribosome display and immobilized model membranes was effective as an in vitro high-throughput screening system and enabled us to identify motif sequences (ALR, KVL) that selectively recognized the bacterial membrane. Owing to host toxicity, it was not possible to enrich any sequence expected to show antimicrobial activity using another in vitro system, e.g. phage display. The synthetic peptides designed from these enriched motifs acted selectively on the bacterial model membrane and showed antibacterial activity. Moreover, the motif sequence conferred selectivity onto native peptides lacking selectivity, and decreased mammalian cell toxicity of native peptides without decreasing their antibacterial activity.
authors.affiliation: National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Xie
authors.forename: Shigeru
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Zhesheng
authors.initials: Z
authors.lastname: Wen
authors.forename: Setsuko
authors.initials: S
authors.lastname: Niimi
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kumano
authors.forename: Yoshikiyo
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: Sachiko
authors.initials: S
authors.lastname: Machida
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism*; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism*; D002942:Circular Dichroism; D020650:Combinatorial Chemistry Techniques; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005452:Fluoresceins / Q000378:metabolism; D008081:Liposomes; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D012270:Ribosomes
chemical_list: D000890:Anti-Infective Agents; D005452:Fluoresceins; D008081:Liposomes; D008567:Membranes, Artificial; D019151:Peptide Library; D010455:Peptides; C007740:fluorexon