by PhilipJ on 1 June 2006
David Goodsell’s molecule of the month for June:
Do you remember the first time that you saw a firefly? If you live anywhere between the Rocky Mountains and the east coast of the US, you have probably chased fireflies since you were a child. If you live in other parts of the world, like me, you may have had the pleasure of discovering fireflies during a summer vacation. They are one of the delightful wonders of warm summer evenings.
The cool yellowish light of fireflies is created by the enzyme luciferase, shown here from PDB entry 2d1s. The creation of light is not an easy process. It requires a lot of energy—a single photon of green light requires about the same energy as the breaking of eight ATP molecules. So, luciferase uses a very energetic process to create light. It has a cofactor, termed a luciferin, that forms a highly strained complex with oxygen, using an ATP molecule to help set everything up. When this oxygenated luciferin breaks, forming carbon dioxide in the process, it leaves behind a highly excited form that then emits the light.
More, as always, here.