title: Botulinum neurotoxin homologs in non-Clostridium species.
abstract: Clostridial neurotoxins (CNTs) are the deadliest toxins known and the causative agents of botulism and tetanus. Despite their structural and functional complexity, no CNT homologs are currently known outside Clostridium. Here, we report the first homologs of Clostridium CNTs within the genome of the rice fermentation organism Weissella oryzae SG25. One gene in W. oryzae S25 encodes a protein with a four-domain architecture and HExxH protease motif common to botulinum neurotoxins (BoNTs). An adjacent gene with partial similarity to CNTs is also present, and both genes seem to have been laterally transferred into the W. oryzae genome from an unknown source. Identification of mobile, CNT-related genes outside of Clostridium has implications for our understanding of the evolution of this important toxin family.
authors.affiliation: Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mansfield
authors.affiliation: Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Jeremy B
authors.initials: JB
authors.lastname: Adams
authors.affiliation: Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada. Electronic address: acdoxey@uwaterloo.ca.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Doxey
mesh_terms: D001905:Botulinum Toxins / Q000235:genetics* / Q000302:isolation & purification; D003013:Clostridium / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D008969:Molecular Sequence Data; D005810:Multigene Family; D017434:Protein Structure, Tertiary; D013744:Tetanus Toxin / Q000235:genetics* / Q000302:isolation & purification; D058836:Weissella / Q000737:chemistry / Q000235:genetics*
chemical_list: D013744:Tetanus Toxin; D001905:Botulinum Toxins
keywords: Botulinum neurotoxin; Clostridial neurotoxin; Clostridium; Lateral gene transfer; Toxin; Weissella