STOCKHOLM - Three scientists who produced atom-by-atom maps of the mysterious, life-giving ribosome won the Nobel chemistry prize Wednesday for a breakthrough that has allowed researchers to develop powerful new antibiotics.

While DNA molecules contain the blueprint for life inside each cell of every organism, it is the ribosome that translates that information into life.

Israeli Ada Yonath and Americans Venkatraman Ramakrishnan and Thomas Steitz shared the 10 million Swedish crowns (897,309 pound) prize for showing how the ribosome, which produces protein, functions at the atomic level.

As ribosomes are crucial to life, they are also a major target for new antibiotics, the Nobel Committee for Chemistry at the Royal Swedish Academy of Sciences said in a statement.

The academy said many of today's antibiotics cure various diseases by blocking the function of bacterial ribosomes.

Yonath, a professor at the Weizmann Institute of Science in Israel, told a news conference by telephone that she was elated to receive the award: It is above and beyond my dreams.

All three scientists have used a method called X-ray crystallography to map the position for each of the hundreds of thousands of atoms that make up the ribosome.

Yonath made the initial breakthrough at the end of the 1970s when she first tried to generate X-ray crystallographic structures of the ribosome, a feat most considered impossible.

The method involves aiming X-rays towards a crystal, which then scatter when they hit atoms. By looking at how the rays spread out, scientists can determine how atoms are positioned.

Yonath started by taking a micro-organism found in the nearby Dead Sea and crystallising its ribosomes. She did this by freezing them at nearly minus 200 degrees Celsius.

Jeremy Berg, director of the U.S. National Institute of General Medical Sciences which funded all three scientists, told Reuters he was amazed at how intrepid Yonath was.

I remember at the time being just completely stunned that she was somewhere between brave enough and crazy enough because it was way, way, way beyond the technnology available at that point, he said.

It would take another 20 years before a full map could be made. During that time, two others joined the race: Yale University's Steitz and Indian-born Ramakrishnan of the MRC Laboratory of Molecular Biology in Britain.

In 1998, Steitz published the first crystal structure of a large part of a ribosome, something that looked like a dim photograph. The three scientists reached the finish line almost simultaneously in 2000, publishing crystal structures that were sharply enough defined to locate atoms.

Ramakrishnan paid tribute to those who worked beside him.

I have to say that I am deeply indebted to all of the brilliant associates, students and post docs who worked in my lab as science is a highly collaborative enterprise, he said in a statement.

Scientists use ribosome models to develop antibiotics that can fight harmful bacteria.
Peter Brezinski, a member of the chemistry panel at the Royal Academy of Sciences in Stockholm, said researchers have only just begun to tap into the potential these models offer.

Fifty percent of all antibiotics target the ribosome, and now we have the tools to begin looking at if there are other substances we can fit into different slots to block and disturb bacteria in our bodies, he said.

The Nobel prizes are handed out annually for achievements in science, peace, literature and economics. This was the third of this year's Nobel prizes, following awards for medicine or physiology Monday and for physics Tuesday.

Prizes for the sciences and for peace were established in the will of 19th century dynamite tycoon Alfred Nobel and have been handed out since 1901. Sweden's central bank began awarding a prize for economics in 1969.

This is the second protein-related prize in a row. Last year's chemistry Nobel was awarded to researchers for the discovery of a glowing jellyfish protein that makes cells, tissues and even organs light up.

Previous winners have included Marie Curie, who won the 1911 prize and is remembered for her contribution to the fight against cancer, and Frederick Sanger, who won the 1958 prize for his work on the structure of proteins, especially insulin.

(Editing by Ralph Boulton)

(Additional reporting by Niklas Pollard and Adam Cox in Stockholm, Kate Kelland in London and Maggie Fox in Washington)