Medical News Today tells of an advance by teams at Rutgers, UCLA, and Institut Jacques Monod in Paris on figuring out how an important molecular machine in nature does its job. Some excerpts:
Two papers by Ebright and collaborators in the Nov. 17 issue of the journal Science define for the first time the mechanisms by which the machine begins synthesis of RNA and then breaks free from its initial binding site to move along DNA to continue synthesizing RNA…
“Our findings were made possible by newly developed, single-molecule methods,” said Ebright, a Howard Hughes Medical Institute investigator and professor of chemistry and chemical biology at Rutgers, The State University of New Jersey. “These methods enabled us to analyze and manipulate individual molecules of the machine, one-by-one, as they carried out reactions”…
“The study of molecular machines and the dynamics of their moving parts hold great interest for nanotechnologists,” said Weiss, leader of the UCLA group…
Taken together, the two studies answer the longstanding question of how the machine acquires the energy required to break its interactions with, and leave, the start site. The machine acquires this energy by unwinding DNA and pulling unwound DNA during initial transcription. As DNA is unwound, energy is stored in the system, in the same manner, Ebright notes, as winding the rubber band of a rubber-band-powered airplane stores energy. Eventually, there is sufficient energy stored in the system that the machine is able to break its interactions with the start site, to shoot forward and, at the same instant, to rewind the unwound DNA.
This is important for at least two reasons: (1) it may help us address current medical problems, as described in the article, and (2) seeing how nature accomplishes its wonders using molecular machines will help us design and build our own new ones, for new wonders to come.
Richard Ebright of Rutgers, one of the team leaders, is a gutsy guy. He organized over 750 microbiologists to protest the current Administration’s approach to bioterror research. See the news story and an interview of Ebright. —Christine
