title: Oligomerization and pore formation of a sphingomyelin-specific toxin, lysenin.
abstract: Lysenin is a novel protein derived from coelomic fluid of the earthworm Eisenia foetida, which specifically recognizes sphingomyelin and induces cytolysis. The mechanism underlying lysenin-induced cell lysis has not been clarified. In this report we studied the interaction of lysenin with red blood cells as well as artificial liposomes. Our results showed that lysenin bound membranes and assembled to SDS-resistant oligomers in a sphingomyelin-dependent manner, leading to the formation of pores with a hydrodynamic diameter of approximately 3 nm. Antibody scanning analysis suggested that the C-terminal region of lysenin was exposed, whereas the N-terminal was hidden in the isolated oligomer complex. Differential scanning calorimetry revealed that lysenin interacted with both hydrophilic head group and hydrophobic hydrocarbon tails of sphingomyelin. Oligomerization but not binding was affected by the amide-linked fatty acid composition of sphingomyelin, suggesting the role of membrane fluidity in the oligomerization step.
authors.affiliation: Supra-Biomolecular System Research Group, RIKEN (Institute of Physical and Chemical Research) Frontier Research System, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamaji-Hasegawa
authors.forename: Asami
authors.initials: A
authors.lastname: Makino
authors.forename: Takeshi
authors.initials: T
authors.lastname: Baba
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Senoh
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kimura-Suda
authors.forename: Satoshi B
authors.initials: SB
authors.lastname: Sato
authors.forename: Nobuo
authors.initials: N
authors.lastname: Terada
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ohno
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kiyokawa
authors.forename: Masato
authors.initials: M
authors.lastname: Umeda
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000648:ultrastructure; D006461:Hemolysis / Q000187:drug effects; D046911:Macromolecular Substances; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009835:Oligochaeta; D018272:Porins / Q000187:drug effects / Q000648:ultrastructure; D011506:Proteins / Q000737:chemistry* / Q000502:physiology / Q000633:toxicity; D012756:Sheep; D013109:Sphingomyelins / Q000737:chemistry*; D013816:Thermodynamics; D014118:Toxins, Biological
chemical_list: D046911:Macromolecular Substances; D018272:Porins; D011506:Proteins; D013109:Sphingomyelins; D014118:Toxins, Biological; C107040:lysenin