Structure of chemokine-derived antimicrobial Peptide interleukin-8alpha and interaction with detergent micelles and oriented lipid bilayers.
Interleukin-8alpha (IL-8alpha) is an antimicrobial peptide derived from the chemokine IL-8. Solution NMR was used to determine the atomic-resolution structure of IL-8alpha in SDS micelles. Solid-state NMR and tryptophan fluorescence were used to probe the interaction of IL-8alpha with model membranes. The peptide interacted differently with anionic versus purely zwitterionic micelles or bilayers. Tryptophan fluorescence demonstrated a deeper position of Trp4 in SDS micelles and POPC/POPG bilayers compared to pure POPC bilayers, consistent with (2)H order parameters, which also indicated a deeper position of the peptide in POPC/POPG bilayers compared to POPC bilayers. Paramagnetic probe data showed that IL-8alpha was situated roughly parallel to the SDS micelle surface, with a slight tilt that positioned the N-terminus more deeply in the micelle compared to the C-terminus. (15)N solid-state NMR spectra indicated a similar, nearly parallel position for the peptide in POPC/POPG bilayers. (31)P and (2)H solid-state NMR demonstrated that the peptide did not induce the formation of any nonlamellar phases and did not significantly disrupt bilayer orientation in aligned model membranes composed of POPC or POPC and POPG.
Bourbigot
Sarah
S
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada.
Fardy
Liam
L
Waring
Alan J
AJ
Yeaman
Michael R
MR
Booth
Valerie
V
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003902:Detergents / Q000737:chemistry*; D016209:Interleukin-8 / Q000737:chemistry*; D008051:Lipid Bilayers; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D003902:Detergents; D016209:Interleukin-8; D008051:Lipid Bilayers; D008823:Micelles; D012967:Sodium Dodecyl Sulfate