Bruce R. Branchini
Sharing MCB Science: The Biochemistry of Bioluminescence
The work of Dr. Bruce R. Branchini, Professor of Chemistry at Connecticut College, has focused on investigating the biochemistry underlying the emission of light by the firefly. The chemicals responsible for the production of light (bioluminescence) in the common North American firefly were identified by scientists whose work began about 65 years ago at Johns Hopkins University.
For the firefly lanterns to glow brightly with the characteristic yellow-green color many of us recall seeing as young children, an organic compound called luciferin must react with ATP (the universal energy source used by all living organisms) and with molecular oxygen from the air we breathe. A special protein called luciferase is needed to catalyze or orchestrate the entire process. The light we see comes from a product of the reaction called oxyluciferin. As the name implies, an oxidation process takes place, similar in many ways to the process involved when a piece of paper is burned in air. There is one important difference, though; while burning paper produces heat, bioluminescence does not – it is cold light. Dr. Branchini’s research team at Connecticut College has been trying to figure out how this oxidation process works differently in the firefly tail and they recently have found the key.
This research team has recently found evidence that molecular oxygen is converted into a very reactive form called superoxide ion. The evidence that superoxide ion drives the process of light emission was determined with the help of Dr. Brudvig at Yale University with a special instrument that uses magnet fields and microwaves. Dr. Branchini thinks that superoxide could be a key ingredient in the emission of light of bioluminescent organisms found on land and in the ocean where the deep ocean glows brightly from hundreds, perhaps thousands of bioluminescent organisms.
As a broader impact of this research, Dr. Branchini has maintained a research group that includes undergraduate participants during the academic year and summers. The students attend research group meetings, participate in college wide summer research programs and present their results off campus. Munya Talukder, undergraduate student at Connecticut College, recently won a poster prize at the Northeast Undergraduate Research and Development Symposium (NURDs) that includes travel funds to the annual ASBMB meeting.
Dr. Branchini also added, “Our recent research has made an important advance in our knowledge of the fundamental process of how chemical energy can be converted into light by living organisms.”
The findings of this research are described in a research article recently published in the Journal of the American Chemical Society.
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