title: Stability of the Clostridium botulinum type A neurotoxin complex: an empirical phase diagram based approach.
abstract: Clostridium botulinum type A neurotoxin (BoNT/A complex) is of great interest to the pharmaceutical industry. The drug itself is a natural complex of the toxin and a number of associated proteins. Surprisingly, relatively little is known about the exact structure and stability of the 900 kDa BoNT/A complex and its component proteins with the exception of the 150 kDa neurotoxin. In this study we describe the relative stability of the BoNT/A complex, the neurotoxin, and its associated proteins over a wide range of temperature and pH employing circular dichroism, intrinsic and 8-anilino-1-naphthalene sulfonate (ANS) fluorescence, and static light scattering. The data suggest a strong stabilizing effect of the associated proteins on the neurotoxin component. This data is compiled into empirical phase diagrams which permit the simultaneous visualization of multiple data sets over a wide range of conditions.
authors.affiliation: Department of Pharmaceutical Chemistry, 2030 Becker Drive, University of Kansas, Lawrence, Kansas 66047, USA.
authors.forename: Duane T
authors.initials: DT
authors.lastname: Brandau
authors.forename: Sangeeta B
authors.initials: SB
authors.lastname: Joshi
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Smalter
authors.forename: Seonyoung
authors.initials: S
authors.lastname: Kim
authors.forename: Bryan
authors.initials: B
authors.lastname: Steadman
authors.forename: C Russell
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D002942:Circular Dichroism; D047013:Clostridium botulinum type A / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D004355:Drug Stability; D005456:Fluorescent Dyes / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008027:Light; D008970:Molecular Weight; D009498:Neurotoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D009498:Neurotoxins; C027132:1-anilino-8-naphthalenesulfonate