- Scientists create a new ‘glowing protein’ that can advance fluorescence microscopy.
- Unlike other green fluorescent protein, it is miniature, thermostable (up to 68°C), and doesn’t require oxygen to emit light.
The discovery of a green fluorescent protein in the 1960s started a new era in cell and molecular biology. It enabled scientists to apply molecular cloning techniques, and monitor cellular processes in living organisms using optical microscopy.
Now, an international team of biophysicists led by the Moscow Institute of Physics and Technology has engineered a new fluorescent protein that is quite different than the existing ones. Besides glowing when exposed to blue and ultraviolet light, it is exceptionally small and stable under high temperatures.
This new ‘glowing protein’ can advance fluorescence microscopy, which is often used to image particular features of tiny specimens like microbes. This technique is also used to image the genetic material within a cell and study infectious diseases, organ development, and much more.
Fluorescence microscope uses a much higher intensity light source than traditional microscopes to excite a fluorescent species in a sample. After being exposed to a laser of a particular wavelength, the fluorescent species emits light at a different wavelength.
This induced ‘glow’ is then analyzed by the fluorescence microscope. These fluorescent proteins are appended to other proteins [through genetic engineering] to observe cell behavior of the later ones.
The technique proved so valuable that the 2014 Nobel Prize in chemistry was awarded for radically improving the accuracy of Fluorescence microscopy. It brought optical microscopy into the nanodimension.
Bacterial genetically altered to create a fluorescent protein | Credit: MIPT
However, fluorescent proteins used for such observations have various shortcomings: they are quite bulky, vulnerable to heat, and glow only in the presence of oxygen.
Thermostable Flavin-based Fluorescent Protein
The newly engineered fluorescent protein overcomes all these shortcomings. It is miniature, thermostable (up to 68°C), and doesn’t require oxygen to emit light.
Researchers found this protein with exceptional properties in the cells of a thermophile – an organism that thrives at high temperatures ranging from 41°C to 122°C. They then genetically engineered a DNA sequence which is responsible for reproducing the protein’s fluorescent component. They left out other segments that would make the molecule bigger.
3D structure of new ‘glowing’ protein | Credit: MIPT
Finally, they added the gene that encodes the proteins into another bacterium’s cells, turning it into a fluorescent protein with unique characteristics.
Overall, this ‘glowing’ protein, due to its ease of crystallization and unexpected stability, seems to be a promising model for ultra-high resolution structural studies of plants, bacteria, and fungi. It can help scientists extract valuable data from cell life and death.
The new protein, if coupled with recent advances in confocal and widefield fluorescence microscopy, can provide invaluable services in several thousands of live-cell imaging experiments.