CAMBRIDGE, Mass., Oct. 9 (UPI) -- U.S. scientists have found a simple circadian clock found in some bacteria operates by the addition and subtraction of phosphate groups on a single protein.
The researchers at Harvard University and the Howard Hughes Medical Institute discovered the clock operates by the rhythmic addition and subtraction of phosphate groups at two key locations, influenced by two other proteins, driving phosphorylation to oscillate according to a remarkably accurate 24-hour cycle.
The work builds upon research reported in 2005 by biologist Takao Kondo and colleagues at Nagoya University. That team initially reported a circadian clock could be reconstituted in a test tube solely with three proteins and ATP.
"The most striking feature of this circadian oscillator is its precision," said Harvard Professor Erin O'Shea. "Even in the absence of external cues -- in total darkness -- these minuscule protein-based clocks can maintain precision to a small fraction of a day over several weeks."
O'Shea, postdoctoral researcher Michael Rust, graduate student Joseph Markson and colleagues report their research in the journal Science.
