Channel-forming membrane permeabilization by an antibacterial protein, sapecin: determination of membrane-buried and oligomerization surfaces by NMR.
The action mechanism of sapecin, an antibacterial peptide with membrane permeabilization activity, was investigated. The dose dependence of the membrane permeabilization caused by sapecin was sigmoidal, suggesting that sapecin oligomerization leads to the membrane permeabilization. Solution nuclear magnetic resonance analysis of the sapecin-phospholipid vesicle complex revealed the surface buried in the membrane and oligomerization surface on the sapecin molecule. The membrane-buried surface of sapecin was determined by observing the transferred cross-saturation phenomena from the alkyl chains of the phospholipid vesicle to the amide protons of sapecin. The membrane-buried surface contains basic and highly exposed hydrophobic residues, which are suitable for interacting with the acidic bacterial membrane. The oligomerization surface was also identified by comparisons between the results from hydrogen-deuterium exchange experiments and transferred cross-saturation experiments. On the basis of the results from the NMR experiments we built a putative model of sapecin oligomers, which provides insights into the membrane permeabilization caused by insect defensins.
Takeuchi
Koh
K
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Takahashi
Hideo
H
Sugai
Mariko
M
Iwai
Hideo
H
Kohno
Toshiyuki
T
Sekimizu
Kazuhisa
K
Natori
Shunji
S
Shimada
Ichio
I
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D066298:In Vitro Techniques; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D008081:Liposomes; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance
D000900:Anti-Bacterial Agents; D019476:Insect Proteins; D008081:Liposomes; D011994:Recombinant Proteins; C057638:sapecin protein, Sarcophaga