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Characterization of surface layer proteins from different Clostridium difficile clinical isolates
M Cerquetti1, A Molinari, A Sebastianelli
1Department of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, viale Regina Elena 299, Rome, 00161, Italy.
Microbial Pathogenesis
|June 7, 2000
Summary
Clostridium difficile strains commonly possess a surface layer (S-layer) composed of two distinct glycoproteins. These S-layer proteins exhibit conserved structural motifs, indicating heterogeneity within the S-layer structure.
Area of Science:
- Microbiology
- Cell Biology
- Protein Structure
Background:
- Previous research suggested two surface proteins in Clostridium difficile are involved in forming an external S-layer.
- The S-layer's role in C. difficile pathogenesis and structure requires further investigation.
Purpose of the Study:
- To investigate the S-layer structure and protein composition across multiple C. difficile strains.
- To characterize the heterogeneity and conserved features of S-layer glycoproteins.
Main Methods:
- Utilized freeze-etching and negative staining techniques to visualize cell surface structures.
- Isolated and characterized S-layer proteins using molecular mass, antigenic cross-reactivity, and N-terminal sequence analysis.
Main Results:
- Detected two superimposed S-layer lattices with square (outer) and hexagonal (inner) symmetry on C. difficile strains.
- Identified two distinct S-layer glycoproteins (36-56 kDa) per strain.
- Demonstrated antigenic cross-reactivity among higher molecular mass S-layer proteins and conserved N-terminal motifs within high and low molecular mass groups.
Conclusions:
- The presence of S-layer is common in C. difficile strains.
- S-layer glycoproteins exhibit heterogeneity but possess conserved structural elements.
- These findings contribute to understanding C. difficile cell surface architecture and potential antigenic variation.