posters 5th Asia-Pacific NMR Symposium 2013

Structure-Function Relationship of the Insect Antimicrobial Peptide, Papiliocin and Its Analogs Isolated from the swallowtail butterfly, Papilio xuthus (#164)

Eunjung lee 1 , Jin-Kyoung Kim 1 , Areum Shin 1 , Ki-Woong Jeong 1 , Yangmee Kim 1
  1. Department of Bioscience and Biotechnology, Institute of SMART Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea

Papiliocin is a well-studied antimicrobial peptide that is isolated from the swallowtail butterfly, Papilio xuthus. Papiliocin is a novel antibiotic possessing low toxicity against mammalian cells and remarkable bacterial cell selectivity. To understand structure-activity relationships, the three dimensional structure of papiliocin was determined in 300 mM dodecylphosphocholine (DPC) micelles by NMR spectroscopy, showing that papiliocin has N-terminal α-helical structure from Lys3 to Lys21 linked to a hydrophobic C-terminal helix from Ala25 to Val36 by a hinge region. Interactions between papiliocin and LPS studied using tryptophan blue-shift data and STD-NMR experiments revealed that Trp2 and Phe5 at N-terminal helix play an essential role in attracting papiliocin into the cell membrane of Gram-negative bacteria. To investigate functional importance of N-terminal and C-terminal helix as well as the aromatic residues, five papiliocin analogs were designed. Two 22-mer analogs composed of N-terminal helix, PapN including N-terminal helix from Arg1 to Ala22 of papiliocin and PapN-FW with exchange of Trp2 and Phe5 in PapN, showed anti-inflammatory activity as well as antimicrobial activity against Gram-negative bacteria without toxicity against mammalian cells. Fluorescence dye leakage experiments revealed that Trp2 in PapN and Trp5 in PapN-FW play key roles in targeting the bacterial cytoplasmic membrane similar to Trp2 in papiliocin. Furthermore, hydrophobic interactions between the C-terminal helix of papiliocin and the hydrophobic portion of LPS or other Gram-negative bacteria cell components provide papiliocin with selectivity against Gram-negative bacterial membranes including LPS.

  1. J.-K. Kim, E. Lee, S. Shin, K-W. Jeong, J-Y. Lee, S.-Y. Bae, S.-H. Kim, J. Lee, S. R. Kim, D. G. Lee, J.-S. Hwang, Y. Kim, Structure and Function of Papiliocin with Antimicrobial and Anti-inflammatory Activities Isolated from the Swallowtail Butterfly, Papilio xuthus, J. Biol. Chem. 286 (2011) 41296-41311