title: The cytotoxic fimbrial structural subunit of Xenorhabdus nematophila is a pore-forming toxin.
abstract: We have purified a fimbrial shaft protein (MrxA) of Xenorhabdus nematophila. The soluble monomeric protein lysed larval hemocytes of Helicoverpa armigera. Osmotic protection of the cells with polyethylene glycol suggested that the 17-kDa MrxA subunit makes pores in the target cell membrane. The internal diameter of the pores was estimated to be >2.9 nm. Electron microscopy confirmed the formation of pores by the fimbrial subunit. MrxA protein oligomerized in the presence of liposomes. Electrophysiological studies demonstrated that MrxA formed large, voltage-gated passive-diffusion channels in lipid bilayers.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Jyotirmoy
authors.initials: J
authors.lastname: Banerjee
authors.forename: Jitendra
authors.initials: J
authors.lastname: Singh
authors.forename: Mohan Chandra
authors.initials: MC
authors.lastname: Joshi
authors.forename: Shubhendu
authors.initials: S
authors.lastname: Ghosh
authors.forename: Nirupama
authors.initials: N
authors.lastname: Banerjee
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D036781:Fimbriae Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010861:Fimbriae, Bacterial / Q000737:chemistry; D006434:Hemocytes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006460:Hemolysin Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007313:Insecta / Q000166:cytology; D007814:Larva / Q000166:cytology; D008051:Lipid Bilayers / Q000378:metabolism; D008854:Microscopy, Electron; D008970:Molecular Weight; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D020593:Xenorhabdus / Q000737:chemistry*
chemical_list: D006460:Hemolysin Proteins; D008051:Lipid Bilayers; D021122:Protein Subunits; D036781:Fimbriae Proteins