[The Scientist] Posted by Victoria Stern

 

 

Three researchers who made fundamental discoveries on the structure and function of the ribosome will receive the Nobel Prize for Chemistry this year. Understanding how the ribosome works at the atomic level has been crucial for understanding key cellular processes underlying life.

Venkatraman Ramakrishnan Image: MRC Laboratory of Molecular Biology

Venkatraman Ramakrishnan, a molecular and cell biologist at MRC Laboratory of Molecular Biology in Cambridge, UK, Thomas Steitz, a Howard Hughes Medical Institute molecular biochemist at Yale University, and Ada Yonath, a structural biologist at the Weizmann Institute of Science in Rehovot, Israel, will share the prize equally.

"I'm very pleased. I think the committee got it right," Peter Moore, a biochemist at Yale University who has worked extensively with Steitz and Ramakrishnan, told The Scientist. "I'm just delighted to see the structure determination recognized by the Nobel committee."

The trio's work "really represents the key scientific discoveries in our understanding of how ribosomes operate. Their discoveries have huge medical importance and also represent a huge feat in our basic understanding of how life works," William Clemons, a chemist at California Institute of Technology who did his PhD thesis in Ramakrishnan's lab, told The Scientist.

Thomas A. Steitz Image: Michael Marsland/Yale University

At the beginning of the 1950s, scientists realized that ribosomes, large complexes of RNA and protein, were critical to protein synthesis and the overall function of the cell. But how they worked at the atomic level was a mystery. At the end of the 1970s, Ada Yonath decided she was going to generate crystal structures of the ribosome using x-ray crystallography to establish the exact location of every atom -- considered an impossible task at the time because of the structure's complexity.

The ribosome contains hundreds of thousands of atoms and two main subunits. The smaller subunit binds messenger RNA and helps form peptide bonds. The larger subunit catalyzes the bond.

Ada E. Yonath Image: Weizmann Institute of Science

Yonath was the first to try to uncover the roles of each subunit. In 1980, she generated the first three-dimensional crystals of the ribosome's large subunit. Twenty years later, she crystallized ribosomes from the bacterium Haloarcula marismortui found in the Dead Sea, and produced an image that gave the location of each atom in the ribosome.

After Yonath's initial findings came to light, Steitz and Ramakrishnan became key players in the effort to map the ribosome's structure by using x-ray crystallography. In 1999, Steitz published the first complete crystal structure of the ribosome's large subunit, and that same year, Ramakrishnan published an image of the structure of the smaller subunit.

Over the past decade, all three researchers have homed in on ever-greater resolution of the ribosome's structure, allowing them to determine atomic locations with more specificity and map ribosome function at the most basic atomic level. Steitz and his colleagues have also been working on using their understanding of ribosomes to create new antibiotics. Most recently, Ramakrishnan and Steitz both reported high resolution crystal structures of ribosomal complexes that gave more insight into how peptide bonds form.

"I'm certainly very happy for the three who have gotten the prize," said Joachim Frank, a biochemist at Columbia University who works on ribosomal function. "All three have made very momentous contributions to the field."

Jeremy Berg, director of the National Institute of General Medical Sciences noted, however, that "one bit of controversy which will likely come up today is how to get four deserving candidates for the Nobel down to three. One key person, Harry Noller at [the University of California, Santa Cruz] was not chosen for the award."

"If the Nobel committee didn't have the rule of three, Harry Noller would have most certainly been included today," said Moore. "They chose the three senior people involved in determining the crystal structure of the ribosome."

"What's great is that the ribosome has come into public focus. It's such an incredible structure and the basis of all life," added Frank. "This is not the end of the story, however. There are many more surprising discoveries" to come.