title: Molecular composition and extinction coefficient of native botulinum neurotoxin complex produced by Clostridium botulinum hall A strain.
abstract: Seven distinct strains of Clostridium botulinum (type A to G) each produce a stable complex of botulinum neurotoxin (BoNT) along with neurotoxin-associated proteins (NAPs). Type A botulinum neurotoxin (BoNT/A) is produced with a group of NAPs and is commercially available for the treatment of numerous neuromuscular disorders and cosmetic purposes. Previous studies have indicated that BoNT/A complex composition is specific to the strain, the method of growth and the method of purification; consequently, any variation in composition of NAPs could have significant implications to the effectiveness of BoNT based therapeutics. In this study, a standard analytical technique using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and densitometry analysis was developed to accurately analyze BoNT/A complex from C. botulinum type A Hall strain. Using 3 batches of BoNT/A complex the molar ratio was determined as neurotoxin binding protein (NBP, 124 kDa), heavy chain (HC, 90 kDa), light chain (LC, 53 kDa), NAP-53 (50 kDa), NAP-33 (36 kDa), NAP-22 (24 kDa), NAP-17 (17 kDa) 1:1:1:2:3:2:2. With Bradford, Lowry, bicinchoninic acid (BCA) and spectroscopic protein estimation methods, the extinction coefficient of BoNT/A complex was determined as 1.54 ± 0.26 (mg/mL)(-1)cm(-1). These findings of a reproducible BoNT/A complex composition will aid in understanding the molecular structure and function of BoNT/A and NAPs.
authors: Botulinum Research Center and Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA.
authors: Anne-Marie
authors: AM
authors: Bryant
authors: Jenny
authors: J
authors: Davis
authors: Shuowei
authors: S
authors: Cai
authors: Bal Ram
authors: BR
authors: Singh
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D019274:Botulinum Toxins, Type A / Q000737:chemistry* / Q000378:metabolism; D003014:Clostridium botulinum / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight
chemical_list: D001426:Bacterial Proteins; D019274:Botulinum Toxins, Type A