MOLECULAR CONSTRUCTION OF CLOSTRIDIUM-BOTULINUM TYPE-C PROGENITOR TOXIN AND ITS GENE ORGANIZATION

The 16S progenitor toxin of Clostridium botulinum type C is made up by conjugation of a neurotoxin with nontoxic components designated as no ntoxic-nonHA and hemagglutinin (HA). The HA was found to be composed o f subcomponents having 53, 33, 22 similar to 23, and 17 kDa molecular masses. Since we previously determined the whole nucleotide sequences of the genes for neurotoxin, nontoxic-nonHA, and HA-33, the cloning an d nucleotide sequencing of the genes for the remaining HA subcomponent s were performed. Two open reading frames coding for 16.7 kDa (HA-17) and 70.6 kDa proteins were identified. The N-terminal amino acid seque nces of HA-53 and HA-22 similar to 23 indicated that the 70.6 kDa prot ein is split into 53 and the 22 similar to 23 kDa proteins alter trans lation and that the 22 similar to 23 kDa protein consists of at least four proteins showing slightly different molecular weights. (C) 1994 A cademic Press, Inc.