14 DAY TRIAL // Scientists at the US Department of Energy's (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) have recently managed to decipher the structure and modus operandi of a remarkable class of ring-shaped protein motors. The team used the state-of-the-art protein crystallography beamline at the Advanced Light Source (ALS), in order to gain deeper insight into the way this small structure functioned, which, in turn, would allow them to understand how certain proteins were formed.
This class of motors plays an important part in the gene expression and replication processes that go on inside all living cells, and also contribute to the survival of the cells. On the downside, they also contribute to the perpetuation of a large number of pathogens, including the human papillomavirus (HPV). This agent has been linked to the onset and development of cervical cancer, and vaccines against it are now available for purchase.
The most important achievement that the team made was discovering details of the enzyme known as the Rho transcription termination factor, which plays a huge role in bacterial cells. The formation exhibits a very peculiar structure, which allows it to bind with RNA inside the cell, and then translocate along the acid's strand until the correct point is reached, and its production process is completed.
“We have shown that the Escherichia coli Rho transcription termination factor functions like a rotary engine, much like the motors found on certain classes of propeller airplanes. As the motor spins, fueled by the chemical energy in ATP nucleotides, it pulls RNA strands through its interior, an action that enables Rho to walk along RNA chains. Interestingly, the rotary firing order of the motor is biased so that the Rho protein can walk in only one direction along the RNA chain,” James Berger says of the finds. The expert holds joint appointments, in the Berkeley Lab Physical Biosciences Division and the University of California in Berkeley (UCB) Department of Molecular and Cell Biology.
Other researchers on the new paper include Nathan Thomsen, a graduate student in his research group, with whom Berger made the important discovery. The crystallography method the team used allowed the scientists to gain a never-before-achieved insight into the structure of parts of the protein that were until that point still a mystery.