Structural studies of porcine myeloid antibacterial peptide PMAP-23 and its analogues in DPC micelles by NMR spectroscopy.
PMAP-23 is a cathelicidin-derived antimicrobial peptide identified from porcine leukocytes. PMAP-23 was reported to show potent antimicrobial activity against Gram-negative and Gram-positive bacteria without hemolytic activity. To study the structure-antibiotic activity relationships of PMAP-23, two analogues by replacing Trp with Ala were synthesized and their tertiary structures bound to DPC micelles have been studied by NMR spectroscopy. PMAP-23 has two alpha-helices, one from Arg1 to Arg10 in the N-terminal region and the other from Phe18 to Arg23 in the C-terminal region. PMAP-1 (Trp(7)-->Ala) shows similar structure to PMAP-23, while PMAP-2 (Trp(21)-->Ala) has a random structure in the C-terminus. PMAP-2 was found to show less antibacterial and vesicle-disrupting activities than PMAP-23 and PMAP-1 [J. H. Kang, S. Y. Shin, S. Y. Jang, K. L. Kim, and K.-S. Hahm (1999) Biochem. Biophys. Res. Commun. 264, 281-286]. Trp(21) in PMAP-23 which induces an alpha-helical structure in the second alpha-helix is essential for the antibacterial activity of PMAP-23. Also, the fluorescence data proved that Trp(21) at the second alpha-helix is buried deep into the phospholipid in the membrane. Therefore, it implies that Trp(21) in the second alpha-helix at the C-terminus of PMAP-23 may play an important role on the interactions with the membrane and the flexible region including two proline residues may allow this alpha-helix to span the lipid bilayer.
Park
Kyoungsoo
K
Department of Chemistry, Konkuk University, Seoul 143-701, Korea.
Oh
Donghoon
D
Shin
Song Yub
SY
Hahm
Kyung-Soo
KS
Kim
Yangmee
Y
D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D001120:Arginine / Q000737:chemistry; D002942:Circular Dichroism; D007962:Leukocytes / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010452:Peptide Biosynthesis; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013552:Swine; D014364:Tryptophan / Q000737:chemistry
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D008823:Micelles; C086301:porcine myeloid antibacterial peptide 23; D014364:Tryptophan; D001120:Arginine; D000409:Alanine