University of Oregon scientists reveal how coral reefs got the blues

A test tube containing a sample of amFP486 illuminated by ultra-violet light from below. Photo credit: Nathan Henderson, UO Institute of Molecular Biology Full size image available through contact

EUGENE -- University of Oregon scientists report their discovery of the basis for the blue coloration found in many coral reef formations in an article published this week by the Proceedings of the National Academy of Sciences.

Jim Remington and Nathan Henderson of the university's Institute of Molecular Biology describe the crystal structure of a cyan (greenish-blue) fluorescent protein from a sea anemone in the report, which completes the Remington laboratory's systematic study of the five classes of reef chromoproteins.

"Molecular and cellular biologists are familiar with the popular green fluorescent protein, first isolated from a jellyfish, which is used by researchers to label internal structures in living cells," said Remington, a physics professor.

Schematic diagram of the protein structure surrounding the molecular segment responsible for light emission in the cyan fluorescent protein amFP486. Schematic diagram by Jim Remington, UO Institute of Molecular Biology Full size image available through contact

"However, it is less well known that the dramatic coloration of coral reef formations is largely due to four closely related classes of proteins: cyan, green, yellow and red fluorescent proteins. In addition, a fifth class of protein is not fluorescent, but conveys a deep purple coloration to the tentacles of sea anemones and similar animals."

Although the biological function of coral reef coloration is poorly understood, Remington said there is growing concern that "bleaching" of coral reefs may be an early indicator of serious ecological damage due to environmental stresses, possibly resulting from human activities.

Ongoing research may help solve this problem while providing an unrelated bonus.

Computer-generated model of the molecular segment responsible for light emission in the cyan fluorescent protein amFP486. Illustration by Nathan Henderson, UO Institute of Molecular Biology Full size image available through contact

The National Science Foundation funded Remington’s work. Henderson, a doctoral student, is supported by an Institute of Molecular Biology fellowship funded by the National Institutes of Health.

Remington's group includes physicists, chemists and biologists who use an interdisciplinary approach in applying physical techniques to the study of biological molecules, especially the structure, function, and interaction of enzymes and fluorescent proteins.

"Understanding how these organisms tune their coloration to meet specific biological requirements will lead to new tools for molecular and cell biology research," Remington said.

Remington's latest research on the cyan protein (known scientifically as amFP486) is part of a large project underway since 1995. "There is huge interest in fluorescent proteins. They are used by essentially every molecular biology lab in the world to light up and label the interior structures of living cells," he explained. Remington's lab achieved the world's first structure of a fluorescent protein (Green Fluorescent Protein), a discovery published in 1996 by the journal Science.