Related Experiment Video
Updated: Feb 18, 2026
07:10
A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
9.5K
Fluorescent sensors based on bacterial fusion proteins
Batirtze Prats Mateu1, Birgit Kainz, Dietmar Pum
1Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Science Vienna (BOKU), Muthgasse 11, A-1190 Vienna, Austria.
Methods and Applications in Fluorescence
|November 18, 2017
Summary
Researchers developed novel fluorescent sensors using bacterial S-layer proteins as scaffolds. These sensors, based on green and cyan fluorescent proteins, show pH-dependent fluorescence and enhanced intensity in viscous environments.
Area of Science:
- Biotechnology
- Protein Engineering
- Nanomaterials
Background:
- Fluorescent proteins are essential tools in biomedical research and technology.
- Bacterial S-layer proteins offer a robust scaffold for protein immobilization and functionalization.
Purpose of the Study:
- To create a novel fluorescent sensor by fusing green and cyan fluorescent proteins (GFPs and CFPs) with bacterial S-layer proteins.
- To investigate the properties of these fusion proteins, including their pH dependence, stability, and behavior on modified silica particles.
Main Methods:
- Cloning, expression, and purification of S-layer-fluorescent protein fusions (SgsE-EGFP, SgsE-ECFP, SgsE-13aa-ECFP).
- Fluorescence spectroscopy to analyze pH dependence and viscosity effects.
- Reassembly of fusion proteins onto silica particles coated with polyelectrolytes, followed by zeta potential, flow cytometry, and fluorescence microscopy.
Main Results:
- Cyan fluorescent protein (CFP) fusions exhibited greater stability than enhanced green fluorescent protein (EGFP) fusions across pH variations.
- Successful reassembly of fluorescent S-layer proteins onto silica nanoparticles, confirmed by zeta potential measurements.
- Fluorescence intensity was pH-dependent and influenced by the polyelectrolyte coating, suggesting limited exposure of the fluorescent tag.
- Increased viscosity significantly enhanced the fluorescence intensity of all three S-layer fusion proteins.
Conclusions:
- Novel S-layer-based fluorescent fusion proteins were successfully engineered and characterized.
- These fusion proteins demonstrate potential as pH-sensitive fluorescent sensors with tunable properties based on surface interactions.
- The observed viscosity-dependent fluorescence offers new avenues for biosensing applications.
Related Concept Videos
01:24Tagging and Fusion Proteins
8.5K
Proteins are involved in several cellular processes and biochemical reactions. Analyzing a specific protein of interest requires it to be isolated from the other proteins in the cell. This is achieved by overexpressing the specific gene in a suitable host to produce large quantities of the target protein. A tag or label is recombined with the gene to produce a fusion protein containing the target protein and the tag. The tags on these fusion proteins can then be used for easy detection and...
8.5K
02:11Reporter Genes
13.4K
Reporter genes are a type of protein-coding gene that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually produce visually identifiable characteristics like fluorescence and luminescence when expressed along with the gene of interest. Thus, reporter genes “report” the presence or absence of genes of interest in an organism, determine the gene expression pattern, or track the physical location of a DNA segment or protein in the cell.
13.4K