Detection of the HA-33 protein in botulinum neurotoxin type G complex by mass spectrometry.
BACKGROUND
The disease botulism is caused by intoxication with botulinum neurotoxins (BoNTs), extremely toxic proteins which cause paralysis. This neurotoxin is produced by some members of the Clostridium botulinum and closely related species, and is produced as a protein complex consisting of the neurotoxin and neurotoxin-associated proteins (NAPs). There are seven known serotypes of BoNT, A-G, and the composition of the NAPs can differ between these serotypes. It was previously published that the BoNT/G complex consisted of BoNT/G, nontoxic-nonhemagglutinin (NTNH), Hemagglutinin 70 (HA-70), and HA-17, but that HA-33, a component of the protein complex of other serotypes of BoNT, was not found.


METHODS
Components of the BoNT/G complex were first separated by SDS-PAGE, and bands corresponding to components of the complex were digested and analyzed by LC-MS/MS.


RESULTS
Gel bands were identified with sequence coverages of 91% for BoNT/G, 91% for NTNH, 89% for HA-70, and 88% for HA-17. Notably, one gel band was also clearly identified as HA-33 with 93% sequence coverage.


CONCLUSIONS
The BoNT/G complex consists of BoNT/G, NTNH, HA-70, HA-17, and HA-33. These proteins form the progenitor form of BoNT/G, similar to all other HA positive progenitor toxin complexes.
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy, NE, Atlanta, GA, 30341, USA. skalb@cdc.gov.
Suzanne R
SR
Kalb
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy, NE, Atlanta, GA, 30341, USA. jbaudys@cdc.gov.
Jakub
J
Baudys
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy, NE, Atlanta, GA, 30341, USA. jbarr@cdc.gov.
John R
JR
Barr
D001905:Botulinum Toxins / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism*; D002853:Chromatography, Liquid; D003014:Clostridium botulinum / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D053719:Tandem Mass Spectrometry
C118973:hemagglutinin 33 protein, Clostridium botulinum; C488535:botulinum toxin type G; D001905:Botulinum Toxins