Characterization of the genes encoding the botulinum neurotoxin complex in a strain of Clostridium botulinum producing type B and F neurotoxins

• Published in: Current microbiology 1998-11, Vol.37 (5), p.312-318
• Main Authors: Santos-Buelga, J.A. (Institute of Food Research, Reading, UK.), Collins, M.D, East, A.K
• Format: Article
• Language: English
• Subjects: Bacteriology; Base Sequence; Biological and medical sciences; Botulinum Toxins - biosynthesis; Botulinum Toxins - genetics; Botulinum Toxins, Type A; Botulism; Chromosome Mapping; Cloning, Molecular; CLOSTRIDIUM BOTULINUM; Clostridium botulinum - genetics; Clostridium botulinum - metabolism; Electrophoresis, Agar Gel; Fundamental and applied biological sciences. Psychology; GENE; GENES; Genes, Bacterial; Genetics; Humans; Microbiology; Molecular Sequence Data; Multigene Family; Neurotoxins; Polymerase Chain Reaction - methods; Polymorphism, Restriction Fragment Length; Proteins; Sequence Analysis, DNA; Sequence Homology, Amino Acid; TOXINAS; TOXINE; TOXINS
• ISSN: 0343-8651; 1432-0991
• DOI: 10.1007/s002849900384

The organization of the clusters of genes encoding proteins of the botulinum neurotoxin (BoNT) progenitor complex was elucidated in a strain of Clostridium botulinum producing type B and F neurotoxins. With PCR and sequencing strategies, the type B BoNT-gene cluster was found to be composed of genes encoding BoNT/B, nontoxic nonhemagglutinin component (NTNH), P-21, and the hemagglutinins HA-33, HA-17, and HA-70, whereas the type F BoNT-gene cluster has genes encoding BoNT/F, NTNH, P-47, and P-21. Comparative sequence analysis showed that BoNT/F in type BF strain 3281 shares highest homology with BoNT/F of non-proteolytic (group II) C. botulinum whereas NTNH and P-21 in the type F cluster of strain 3281 are more similar to the corresponding proteins in proteolytic (group I) type F C. botulinum. These findings indicate diverse evolutionary origins for genes encoding BoNT/F and its associated non-toxic proteins, although the genes are contiguous. By contrast, sequence comparisons indicate that genes encoding BoNT/B and associated non-toxic proteins in strain 3281 possess a similar evolutionary origin. It was demonstrated that the genes present in the BoNT/B gene cluster of this type BF strain show exceptionally high homology with the equivalent genes in the silent BoNT/B gene cluster of C. botulinum type A(B), possibly indicating their common ancestry