Week 2 Response: Fluorescent Proteins

Anyone have one of these when growing up? Crayola Glow Board Only 10 years old and we were on our way to making our own glowing, neon art pieces!

Neon Blackboard
This is bona-fide renaissance work.

But wait, what’s this? Fluorescent Bacteria This is no Crayola masterpiece—it’s fluorescent bacteria, a work of art in a petri dish! Although some bacteria naturally glow on their own, such as pseudomonas fluorescens and the deadly pseudomonas aeruginosa, the particular bacteria in the picture above glow as a result of the fluorescent proteins in them, derived from GFP (green fluorescent protein) and dsRed (a red fluorescent coral protein). The eight different colors seen in the bacteria are a result of color mutations produced through biologically engineering these two proteins.

How Do Proteins Fluoresce?

Proteins fluoresce when they “[contain] the appropriate amino acids in high enough concentrations and [are] excited with the correct wavelength of ultraviolet light”(CRAIC Technologies). Although there are other contributing factors to fluorescence, the three main amino acids connected to fluorescence are tryptophan, tyrosine, and phenylalanine, with tryptophan glowing significantly strongest (Gabor Mocz).

Excitation Diagram
Excitation Diagram

When electrons absorb enough energy above their baseline energy level (ground state), they become “excited”. Eventually, they release energy when they fall back to their baseline energy level, and that results in UV light, which is why proteins are able to fluoresce (Wikipedia).

The Role of Fluorescent Proteins in Bioimaging

In 2008, Martin Chalfie, Osamu Shimomura, and Roger Y. Tsien were awarded the Nobel Prize in Chemistry for discovering and developing GFP. They also drew that pretty sunset picture. Of course, millions of dollars aren’t poured into research so scientists can draw pictures of sunsets. Just as wildlife researchers may tag individual animals and release them back into the wild to study their behavior, cell biologists can use fluorescent proteins to track the development of cells over time.

Before the development of GFP and other fluorescent proteins, the fluorescent molecules available were “strongly phototoxic in living cells” (Wikipedia). Once the fluorescent molecules were illuminated, the test subject was likely to be fatally poisoned, making the study of living cells difficult. Thanks to fluorescent proteins, however, we can now study living cells with relative ease. Overall, they’re a “powerful toolkit for visualization of structural organization and dynamic processes in living cells and organisms” (Chudakov, Matz, Lukyanov, and Lukyanov). The many different colors available also means we can track certain cells more particularly with multicolor labeling.

Fluorescent Protein Colors
Fluorescent Protein Colors

What Does This Mean for Artists?

Look at that gorgeous palette of colors. It’s like a neon paint set—there’s a vast number of possibilities for artmaking. Not only could we make more pretty pictures of sunsets, we could make them highly dynamic. Maybe only certain colors will glow at a time, depending on the wavelength of the UV light you shine on it. A colony of bacteria could grow its own picture, and every few days the picture might change. You could even insert the fluorescent proteins into a living being and watch the colors shift as the proteins moved around (fluorescent proteins have already been tested in human beings). But of course, working with living beings, especially humans, always leads to controversy. And that would need another post of its own to discuss.

-Kathy Huynh

(P.S. I want to present during week 7!)


One thought on “Week 2 Response: Fluorescent Proteins

  1. There’s an incredibly awesome TedMed talk by UCSD surgeon Quyen Nguyen regarding fluorescent tissue labeling during surgery, it’s just incredible. Here’s a link to the talk.


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