Various new tools allow scientists to see proteins in living cells

Proteins are particularly complex molecules. They are bent and enlaced in various ways to execute reactions which cell metabolism and growth need. But how these miniature machines are integrated together to complete the cell function? With the use of recombinant protein technology, they get some answers.

Innovation is emerging. Bewersdorf team is working with two other research teams to study clickable chemical probes: SNAP-tag of New England Biolabs and HaloTag of Promega Biotech companies. These technologies include a shorter target sequence which can be encoded to the interested protein and a dye molecule which can be embedded in the target protein by a simple chemical reaction. Bewersdorf and his colleagues have demonstrated that the two technologies can make use of organic dyes to function on living cells.

While Selvin lab developed a smaller quantum dot with a diameter of approximately 9 nm. The size allows him to glide the quantum dot between nerve cells in the space of 20 to 40 nm, and signal transduction molecules transmit information to neighboring nerve cells via this place. The lab also plans to perforate the cell membrane and then quickly seal it to prevent damage to cells. "We are able to make a bacterial enzyme called streptolysin to drill a tiny hole about 5 nanometers in the cell membrane." Selvin said. This width is enough to let through a fluorescent protein and even a protein joint with antibody in order to find the target object inside the cell. After that, researchers used the unpublished methods to patch holes in 20 minutes using of recombinant horse proteins.

In addition, there are worries that the probes would interfere with the function of the target protein. While biophysicist Jie Xiao at The Johns Hopkins University has put forward an alternative method that will not damage these proteins.

Her molecules probes don't attach to the targeted after getting genetically modified. After being produced, they are immediately split by a kind of enzymes and enter a specific location of the cell membrane. This means that they no longer carry the location information of the target molecules but they are located in a position where they can accurately calculate them, and thereby obtaining accurate count of protein production. At the same time, the protein itself can function freely. This technology is called CoTrAC.

"Quantifying protein levels in living cells is very important," Xiao explained, "People often use fluorescence to indicate the relative change." But the genes she studied regulate few proteins, and it is difficult to image through super-resolution counting. In addition, subtle changes in the precise number of these proteins also can judge whether there is a change in the state of cells. To learn more about how proteins work and what kinds of recombinant proteins (such as recombinant ACSL3) there have, you can visit Flarebio’s website.