Bioorthogonal Labeling Enables In Situ Fluorescence Imaging of Expressed Gas Vesicle Nanostructures.
Erik SchrunkPrzemys Çaw DutkaRobert C HurtDi WuMikhail G ShapiroPublished in: Bioconjugate chemistry (2024)
Gas vesicles (GVs) are proteinaceous nanostructures that, along with virus-like particles, encapsulins, nanocages, and other macromolecular assemblies, are being developed for potential biomedical applications. To facilitate such development, it would be valuable to characterize these nanostructures' subcellular assembly and localization. However, traditional fluorescent protein fusions are not tolerated by GVs' primary constituent protein, making optical microscopy a challenge. Here, we introduce a method for fluorescently visualizing intracellular GVs using the bioorthogonal label FlAsH, which becomes fluorescent upon reaction with the six-amino acid tetracysteine (TC) tag. We engineered the GV subunit protein, GvpA, to display the TC tag and showed that GVs bearing TC-tagged GvpA can be successfully assembled and fluorescently visualized in HEK 293T cells. Importantly, this was achieved by replacing only a fraction of GvpA with the tagged version. We used fluorescence images of the tagged GVs to study the GV size and distance distributions within these cells. This bioorthogonal and fractional labeling approach will enable research to provide a greater understanding of GVs and could be adapted to similar proteinaceous nanostructures.
Keyphrases
- amino acid
- fluorescence imaging
- living cells
- single molecule
- high resolution
- quantum dots
- binding protein
- photodynamic therapy
- optical coherence tomography
- label free
- high speed
- oxidative stress
- cell cycle arrest
- mass spectrometry
- risk assessment
- machine learning
- cell proliferation
- high throughput
- climate change
- reactive oxygen species
- psychometric properties
- pi k akt