Related Experiment Video
Updated: May 26, 2026
Immuno-fluorescence Assay of Leptospiral Surface-exposed Proteins
Published on: July 1, 2011
Methylation and in vivo expression of the surface-exposed Leptospira interrogans outer-membrane protein OmpL32
Azad Eshghi1, Marija Pinne2,3, David A Haake4,2
1Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.
Abstract:
Recent studies have revealed that bacterial protein methylation is a widespread post-translational modification that is required for virulence in selected pathogenic bacteria. In particular, altered methylation of outer-membrane proteins has been shown to modulate the effectiveness of the host immune response. In this study, 2D gel electrophoresis combined with MALDI-TOF MS identified a Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 protein, corresponding to ORF LIC11848, which undergoes extensive and differential methylation of glutamic acid residues. Immunofluorescence microscopy implicated LIC11848 as a surface-exposed outer-membrane protein, prompting the designation OmpL32. Indirect immunofluorescence microscopy of golden Syrian hamster liver and kidney sections revealed expression of OmpL32 during colonization of these organs. Identification of methylated surface-exposed outer-membrane proteins, such as OmpL32, provides a foundation for delineating the role of this post-translational modification in leptospiral virulence.
Insights
Researchers identified a novel outer-membrane protein, OmpL32, in Leptospira interrogans that is extensively methylated. This modification is crucial for bacterial virulence and immune evasion in pathogenic bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Bacterial protein methylation is a key post-translational modification impacting virulence.
- Outer-membrane protein methylation influences host immune responses in pathogens.
Purpose of the Study:
- To identify and characterize methylated outer-membrane proteins in Leptospira interrogans.
- To investigate the role of protein methylation in leptospiral virulence.
Main Methods:
- 2D gel electrophoresis and MALDI-TOF MS were used to identify methylated proteins.
- Immunofluorescence microscopy localized the identified protein on the bacterial surface and in host tissues.
Main Results:
- A Leptospira interrogans serovar Copenhageni protein (ORF LIC11848) was identified as extensively methylated on glutamic acid residues.
- This protein, designated OmpL32, is surface-exposed and expressed during organ colonization in hamsters.
- OmpL32 methylation is differential, suggesting a regulatory role.
Conclusions:
- OmpL32 is a methylated outer-membrane protein in Leptospira interrogans.
- The identification of OmpL32 provides insights into the role of protein methylation in leptospiral pathogenesis and host immune modulation.
