title: Molecular Assembly of Clostridium botulinum progenitor M complex of type E.
abstract: Clostridium botulinum neurotoxin (BoNT) is released as a progenitor complex, in association with a non-toxic-non-hemagglutinin protein (NTNH) and other associated proteins. We have determined the crystal structure of M type Progenitor complex of botulinum neurotoxin E [PTC-E(M)], a heterodimer of BoNT and NTNH. The crystal structure reveals that the complex exists as a tight, interlocked heterodimer of BoNT and NTNH. The crystal structure explains the mechanism of molecular assembly of the complex and reveals several acidic clusters at the interface responsible for association at low acidic pH and disassociation at basic/neutral pH. The similarity of the general architecture between the PTC-E(M) and the previously determined PTC-A(M) strongly suggests that the progenitor M complexes of all botulinum serotypes may have similar molecular arrangement, although the neurotoxins apparently can take very different conformation when they are released from the M complex.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973.
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Eswaramoorthy
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973.
authors.forename: Jingchuan
authors.initials: J
authors.lastname: Sun
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973.|Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Huilin
authors.initials: H
authors.lastname: Li
authors.affiliation: Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA.
authors.forename: Bal Ram
authors.initials: BR
authors.lastname: Singh
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973.
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Swaminathan
mesh_terms: D000143:Acids / Q000378:metabolism; D001905:Botulinum Toxins / Q000737:chemistry* / Q000648:ultrastructure; D003014:Clostridium botulinum / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D012996:Solutions
chemical_list: D000143:Acids; D012996:Solutions; D001905:Botulinum Toxins; C096326:botulinum toxin type E