Genetically Encoded Fluorescent Biosensor for Rapid Detection of Protein Expression

Area of Science:

• Molecular Biology
• Biotechnology
• Microbiology

Background:

• Fluorescent proteins are essential tools for visualizing protein expression in living organisms.
• A significant limitation is the slow chromophore maturation process, hindering real-time analysis.

Purpose of the Study:

• To engineer a novel genetically encoded biosensor for rapid detection of protein expression in live bacteria.
• To overcome the time delays associated with conventional fluorescent protein maturation.

Main Methods:

• Development of a "Sensor for Transiently Expressed Proteins" (STEP) biosensor.
• Utilizing a pre-matured, dim green fluorescent protein that enhances fluorescence upon specific tag binding.
• Characterization of binding kinetics (Kd, kon) and performance in live *E. coli* cells.

Main Results:

• The STEP biosensor exhibits an 11-fold increase in fluorescence upon specific protein tag binding.
• Achieved rapid detection of protein expression within seconds, significantly faster than standard fluorescent protein fusions.
• Demonstrated high specificity and affinity (Kd 120 nM, kon 1.7 × 10^5 M^-1 s^-1) for the protein tag.

Conclusions:

• The STEP biosensor enables real-time detection of protein expression in live bacteria with unprecedented speed.
• This technology facilitates the study of rapid cellular processes with high spatiotemporal resolution.
• Opens new avenues for live-cell imaging and dynamic biological studies.