Related Experiment Videos
Comparative sequence analysis of the Clostridium difficile toxins A and B
C von Eichel-Streiber1, R Laufenberg-Feldmann, S Sartingen
1Institut für Medizinische Mikrobiologie, Johannes-Gutenberg-Universität, Mainz, FRG.
Molecular & General Genetics : MGG
|May 1, 1992
Summary
Clostridium difficile toxins A and B share significant amino acid homology and structural features, suggesting a common evolutionary origin. Their repetitive C-termini and conserved domains offer insights into toxin function.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Clostridium difficile is a significant cause of antibiotic-associated diarrhea.
- The Toxin locus (tox) of C. difficile VPI 10463 contains genes for toxins A (toxA) and B (toxB).
- Previous studies suggested differences in toxin specificity based on antibody responses.
Purpose of the Study:
- To analyze the structural and functional homologies between Clostridium difficile toxins A and B.
- To investigate the evolutionary relationship between toxA and toxB genes.
Main Methods:
- Sequence analysis of the tox locus and comparison of amino acid sequences of ToxA and ToxB.
- Identification and characterization of conserved domains and repetitive elements within the toxins.
Main Results:
- ToxA and ToxB exhibit 63% amino acid homology.
- Both toxins possess repetitive C-termini (CROPs) and conserved N-terminal domains, including a hydrophobic cluster and a residue-rich sequence.
- Nineteen distinct CROPs were identified in ToxB, grouped into five homologous sets.
Conclusions:
- Structural and functional similarities suggest toxA and toxB evolved from a common ancestor via gene duplication.
- The conserved domains likely play critical roles in toxin activity.
- Further research into these domains may elucidate toxin mechanisms.