In a study published in “Scientific Reports,” Dimitri Deheyn and his colleagues at Scripps Oceanography, the Air Force Research Laboratory and the Salk Institute for Biological Studies have conducted the most detailed examination of green fluorescent proteins (GFPs) in lancelets, marine invertebrates also known as “amphioxus.”
The fish-shaped animals, which spend much of their time in shallow coastal regions mostly burrowed in sand, offer insights on natural fluorescence, since individual specimens can emit bright and much dimmer versions of the light, a rare capability in the animal kingdom.
The study carries implications for a variety of industries looking to maximize brightness of natural fluorescence, including applications in biotechnology such as adapting fluorescence for tracking the expression of specific genes in the human body.
Deheyn and his colleagues found that only a few key structural differences allow the sea creature to emit different brightness levels. The differences relate to changes in stiffness around the animal’s “chromophore pocket,” the area of proteins responsible for molecular transformation of light and thus light output intensity.
“We discovered,” Deheyn said, “that some of the amphioxus GFPs are able to transform blue light into green light with 100 percent efficiency,... which combines with other properties of light absorbance to make the amphioxus GFPs about five times brighter than current commercially available GFPs, resulting in effect to a huge difference.”
The exact mechanism that controls this remains unknown, Deheyn said, adding that this study opens doors toward its understanding.
Amphioxus are thought to use fluorescence as a sunscreen, as an antioxidant and possibly for photo-sensing, using GFPs as receptors to the surrounding light in their environment.
Deheyn said that learning more about bright-emitting GFPs in nature is useful for a variety of applications and fields of science.
“The U.S. Air Force, and the Department of Defense in general, uses a large variety of biosensors in biomedicine, bioengineering and materials science, and providing proteins with the ability to be very bright can help technology advance because of better signal-to-noise ratio.”
Authors of the paper include Erin Bomati of Scripps Oceanography; Joy Haley of the Air Force Research Laboratory; and Joseph Noel of the Salk Institute for Biological Studies. The Air Force Office of Scientific Research supported the study.
--Staff and contribution