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Variation in the surface layer proteins of Clostridium difficile
1Department of Medical Microbiology, University of Edinburgh Medical School, Teviot Place, Edinburgh, EH8 9AG, UK.
FEMS Immunology and Medical Microbiology
|September 11, 2001
Summary
Surface layers (S-layers) of Clostridium difficile exhibit significant protein variability. These S-layer proteins serve as valuable markers for bacterial phenotyping, aiding in identification and classification.
Area of Science:
- Microbiology
- Bacterial surface structures
- Protein analysis
Background:
- Surface layers (S-layers) are regular crystalline protein structures found on the outermost surface of many bacteria.
- Clostridium difficile features an S-layer composed of two distinct protein subunits.
Purpose of the Study:
- To investigate the variability in molecular mass of S-layer proteins among different Clostridium difficile isolates.
- To assess the potential of S-layer proteins as phenotypic markers for Clostridium difficile.
Main Methods:
- Treatment of whole Clostridium difficile cells with 5 M guanidine hydrochloride.
- Analysis of S-layer proteins using SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis).
- Detection via Coomassie blue staining and immunoblotting.
Main Results:
- Significant variability in the molecular masses of the two major S-layer proteins was observed across 25 isolates.
- Molecular masses ranged from 48 to 56 kDa (heavier protein) and 37 to 45 kDa (lighter protein).
- A consistent 70 kDa protein component was detected in all isolates, and limited cross-reactivity was found between S-layer proteins.
Conclusions:
- The molecular mass of Clostridium difficile S-layer proteins is highly variable among isolates.
- S-layer proteins, when analyzed by Coomassie blue staining and immunoblotting, are a useful marker for bacterial phenotyping.