Center for Relativistic Laser Science

2018 121st KCS General Meeting

Fluorescence imaging is one of the major ways to study the intracellular distribution, structure and function of proteins. Labeling of a protein of interest with a fluorescent probe is often accomplished by organic dyes conjugated to antibodies specific to the protein or genetic incorporation of fluorescence protein fused at one the end of the protein of interest. However, in super-resolution fluorescence microscopy, both labeling method results in expansion of the physical dimensions of the imaged structures because of the distance between protein and fluorophore. Also, the fused fluorescent protein can perturb the endogenous structures due to the large size, the different charge or polarity states and the oligomeric nature. Here, we adapt genetic code expansion which can incorporate unnatural amino acids to the specific residue of a protein of interest. Incorporated unnatural amino acids such as alkyne-derived amino acids enable us to probe the protein of interest with the shortest possible linkage distance between the fluorophore and protein via click reaction between the unnatural amino acid and clickable fluorophore. We expect the incorporated unnatural amino acids to a specific protein in human cells can be utilized in site-specific imaging based on Raman, IR and fluorescence and in spectroscopic studies of proteins inside living human cells. 

Reference

1.  Elsässer, Simon J, et al. “Genetic Code Expansion in Stable Cell Lines Enables Encoded Chromatin Modification.” Nature Methods, vol. 13, no. 2, 2016, pp. 158–164., doi:10.1038/nmeth.3701.