Space filled model of a 70S ribosome.

Now that scientists have determined most of the sequence of chemical units in the human genome, a next step is to unravel the mechanisms directed by the genetic code. Scientists got a close look at some of these mechanisms recently by using synchrotron light sources to make images of RNA polymerase, both subunits of the ribosome, and the full ribosome. These "molecular machines" read the genetic message and accurately make the proteins that form the structures and perform the functions of living organisms. These assemblies have been the subjects of intense study for 30 years, but only recently have advances in synchrotron technology, crystal sample quality, experimental methods, and computational approaches enabled near-atomic resolution of their structures. The new images reveal in minute detail how DNA is unwound, how a message (mRNA) is created with the help of RNA polymerase, how this message is read by a ribosome, and how the ribosome synthesizes protein. The image of the complete ribosome was named by Science magazine as one of the top 10 scientific breakthroughs of 1999. The work was performed at Lawrence Berkeley National Laboratory, Argonne National Laboratory, and Stanford Synchrotron Radiation Laboratory.

Scientific Impact: These images demonstrated that there is much more to ribosomal structures than previously thought. They also helped bolster the theory that RNA molecules were among life's first, with proteins emerging at a later time.

Social Impact: Studies of this type are expected to help lay the groundwork for improved drug design, faster diagnosis of disease, and better disease prevention and treatment methods.

Reference: Jamie H. Cate, Marat M. Yusupov, Gulnara Zh. Yusupova, Thomas N. Earnest, and Harry F. Noller, "X-ray Crystal Structures of 70S Ribosome Functional Complexes," Science 285: 2095-2104 (1999).

Technical Contact: Dr. Roland Hirsch, Medical Sciences Division, Office of Biological and Environmental Research, 301-903-9009

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Biological and Environmental Research