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Functional Roles of Aromatic Residues and Helices of Papiliocin in its Antimicrobial and Anti-inflammatory Activities.

Lee E, Kim JK, Jeon D, Jeong KW, Shin A, Kim Y - Sci Rep (2015)

Bottom Line: PapN exhibited significant broad-spectrum antibacterial activities without cytotoxicity.The PapN series peptides permeabilized bacterial membranes less effectively than papiliocin, showing no antibacterial activities in an hour.The results imply that the Trp(2) and Phe(5) in the amphipathic N-terminal helix are important in the rapid permeabilization of the gram-negative bacterial membrane.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, South Korea.

ABSTRACT
A cecropin-like peptide, papiliocin, isolated from the swallowtail butterfly Papilio xuthus, possesses high selectivity against gram-negative bacteria. Since Trp(2) and Phe(5) are highly conserved residues in cecropin-like peptides, we investigated the role of Trp(2) and Phe(5) in antibacterial activity. Substitution of Trp(2) and Phe(5) in papiliocin with Ala (papiliocin-2A and papiliocin-5A) revealed that Trp(2) is a key residue in its antibacterial activities. In order to understand the structural requirements for papiliocin function and to design shorter, but more potent, peptide antibiotics, we designed papiliocin constructs, PapN (residues Arg(1)-Ala(22) from the N-terminal amphipathic helix). PapN exhibited significant broad-spectrum antibacterial activities without cytotoxicity. Bactericidal kinetics of peptides against E.coli showed that papiliocin completely and rapidly killed E.coli in less than 10 minutes at 2× MIC concentration, while papiliocin-2A and papiliocin-5A killed four times more slowly than papiliocin. The PapN series peptides permeabilized bacterial membranes less effectively than papiliocin, showing no antibacterial activities in an hour. The results imply that the Trp(2) and Phe(5) in the amphipathic N-terminal helix are important in the rapid permeabilization of the gram-negative bacterial membrane. The hydrophobic C-terminal residues permeabilize the hydrophobic bacterial cell membrane synergistically with these aromatic residues, providing selectivity against gram-negative bacteria.

No MeSH data available.


Related in: MedlinePlus

Comparison of 11 known cecropin sequences from ten insects and one mammal.Conserved residues among papiliocin and at least seven other cecropins are in bold. Sequences are arranged according to percent sequence identity to papiliocin to obtain maximal homology (top sequence has highest percent identity).
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f1: Comparison of 11 known cecropin sequences from ten insects and one mammal.Conserved residues among papiliocin and at least seven other cecropins are in bold. Sequences are arranged according to percent sequence identity to papiliocin to obtain maximal homology (top sequence has highest percent identity).

Mentions: Cecropins belong to a large family of cationic α-helical AMPs identified in a broad spectrum of organisms, including gram-positive bacteria, gram-negative bacteria, and fungi1516. Among the insect-derived AMPs, cecropin was the first α-helical form discovered (in 1981) and isolated from the hemolymph of the Cecropia moth1718. A number of cecropin-like peptides composed of 31–42 amino acids have been identified. As shown in Fig. 1, insect cecropin-like peptides are highly positively charged AMPs and share over 50% sequence similarity, excluding moricin. Most cecropin-like peptides in insects have one or two aromatic residues near the N-terminus. The aromatic residues Trp2 and Phe5, in particular, are highly conserved. Tertiary structures have revealed that these peptides are generally composed of an N-terminal amphipathic α-helix and a hydrophobic C-terminal α-helix linked by a hinge region19202122232425. Papiliocin is a novel insect cecropin expressed in the larvae of the swallowtail butterfly, Papilio xuthus26. Papiliocin shares over 78% sequence identity and over 94% sequence similarity with cecropin A from Hyalophora and Bombyx. In our previous study, we showed that papiliocin has high bacterial cell selectivity, particularly against gram-negative bacteria, and potent anti-inflammatory activity. We also determined the structure of papiliocin by NMR spectroscopy. The structure revealed that papiliocin contains an N-terminal α-helix (residues Lys3–Lys21) and a C-terminal hydrophobic α-helix (Ala25–Val35), linked by a hinge region27.


Functional Roles of Aromatic Residues and Helices of Papiliocin in its Antimicrobial and Anti-inflammatory Activities.

Lee E, Kim JK, Jeon D, Jeong KW, Shin A, Kim Y - Sci Rep (2015)

Comparison of 11 known cecropin sequences from ten insects and one mammal.Conserved residues among papiliocin and at least seven other cecropins are in bold. Sequences are arranged according to percent sequence identity to papiliocin to obtain maximal homology (top sequence has highest percent identity).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496781&req=5

f1: Comparison of 11 known cecropin sequences from ten insects and one mammal.Conserved residues among papiliocin and at least seven other cecropins are in bold. Sequences are arranged according to percent sequence identity to papiliocin to obtain maximal homology (top sequence has highest percent identity).
Mentions: Cecropins belong to a large family of cationic α-helical AMPs identified in a broad spectrum of organisms, including gram-positive bacteria, gram-negative bacteria, and fungi1516. Among the insect-derived AMPs, cecropin was the first α-helical form discovered (in 1981) and isolated from the hemolymph of the Cecropia moth1718. A number of cecropin-like peptides composed of 31–42 amino acids have been identified. As shown in Fig. 1, insect cecropin-like peptides are highly positively charged AMPs and share over 50% sequence similarity, excluding moricin. Most cecropin-like peptides in insects have one or two aromatic residues near the N-terminus. The aromatic residues Trp2 and Phe5, in particular, are highly conserved. Tertiary structures have revealed that these peptides are generally composed of an N-terminal amphipathic α-helix and a hydrophobic C-terminal α-helix linked by a hinge region19202122232425. Papiliocin is a novel insect cecropin expressed in the larvae of the swallowtail butterfly, Papilio xuthus26. Papiliocin shares over 78% sequence identity and over 94% sequence similarity with cecropin A from Hyalophora and Bombyx. In our previous study, we showed that papiliocin has high bacterial cell selectivity, particularly against gram-negative bacteria, and potent anti-inflammatory activity. We also determined the structure of papiliocin by NMR spectroscopy. The structure revealed that papiliocin contains an N-terminal α-helix (residues Lys3–Lys21) and a C-terminal hydrophobic α-helix (Ala25–Val35), linked by a hinge region27.

Bottom Line: PapN exhibited significant broad-spectrum antibacterial activities without cytotoxicity.The PapN series peptides permeabilized bacterial membranes less effectively than papiliocin, showing no antibacterial activities in an hour.The results imply that the Trp(2) and Phe(5) in the amphipathic N-terminal helix are important in the rapid permeabilization of the gram-negative bacterial membrane.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, South Korea.

ABSTRACT
A cecropin-like peptide, papiliocin, isolated from the swallowtail butterfly Papilio xuthus, possesses high selectivity against gram-negative bacteria. Since Trp(2) and Phe(5) are highly conserved residues in cecropin-like peptides, we investigated the role of Trp(2) and Phe(5) in antibacterial activity. Substitution of Trp(2) and Phe(5) in papiliocin with Ala (papiliocin-2A and papiliocin-5A) revealed that Trp(2) is a key residue in its antibacterial activities. In order to understand the structural requirements for papiliocin function and to design shorter, but more potent, peptide antibiotics, we designed papiliocin constructs, PapN (residues Arg(1)-Ala(22) from the N-terminal amphipathic helix). PapN exhibited significant broad-spectrum antibacterial activities without cytotoxicity. Bactericidal kinetics of peptides against E.coli showed that papiliocin completely and rapidly killed E.coli in less than 10 minutes at 2× MIC concentration, while papiliocin-2A and papiliocin-5A killed four times more slowly than papiliocin. The PapN series peptides permeabilized bacterial membranes less effectively than papiliocin, showing no antibacterial activities in an hour. The results imply that the Trp(2) and Phe(5) in the amphipathic N-terminal helix are important in the rapid permeabilization of the gram-negative bacterial membrane. The hydrophobic C-terminal residues permeabilize the hydrophobic bacterial cell membrane synergistically with these aromatic residues, providing selectivity against gram-negative bacteria.

No MeSH data available.


Related in: MedlinePlus