Israeli scientist Ada Yonath, a leading researcher in the structural biology field, was awarded a Nobel Prize in chemistry on Wednesday, the Nobel committee in Stockholm announced.

Yonath shares the prize with Britain's Venkatraman Ramakrishnan and Thomas A. Steitz, an American, for studies of the structure and function of the ribosome.

She told reporters after being informed of her victory that from the very beginning her project seemed to her Nobel-worthy, but many along the way had been wary of her ability to see the research through.

"From the first indication that perhaps this project would work, I was told that this was a project of Nobel standards."

At another point, however, she was told that her project would not succeed.

"You won't make it, what you want to do - others have tried and failed, so it won't happen. They gave me the impression that the problems were cardinal, that there was no chance."

Yonat said, recalling her decision to undertake research on ribosomes, "People called me a dreamer."

Prime Minister Benjamin Netanyahu called Yonath to congratulate her and expressed his "enormous pride, along with the entire nation" for her achievement.

"The Nobel Prize is a true Olympics of humanity," said Netanyahu. "It is an enormous achievement."

Yonath has focused her research on the structure of the ribosome, a part of the cell that synthesizes protein and translates genetic code in the production of protein.

Yonath was the first Israeli biologist to work with NASA in sending research material to outer space. She cooperated with NASA on 12 missions. Her research contributed greatly to the development of more effective antibiotics, which can overcome phenomenon of drug resistant pathogens.

Yonath is the fourth woman to win the Nobel chemistry prize and the first since 1964, when Dorothy Crowfoot Hodgkin of Britain received the prize.

"I'm really, really happy," Yonath said "I thought it was wonderful when the discovery came. It was a series of discoveries...We still don't know every, everything, but we progressed a lot."

"I must say I was shocked when they called me and said I was in the leading group. I was sure they were pulling my leg, so I said: 'here, they found themselves a new victim,'" said Yonath.

"I saw the number 46 on the caller ID, the country code for Sweden. So I said, 'they're taking this joke really far,' but the tone was very much Swedish, with a very Swedish accent, so it seemed fine after all."

Yonath is a professor and head researcher in the field of structural biology and biochemistry at the Weizmann Institute of Science in Rehovot.

She has won many prizes for her research in recent years, including the Israel Prize in Chemistry and the Wolf Prize in Chemistry.

This year's three laureates all generated three-dimensional models that show how different antibiotics bind to ribosomes.

It is a matter of having a little faith, said Dr. Jeremy Berg, director of the NIH's National Institute of General Medical Sciences. He was impressed with Yonath's ideas in 1987, when she spoke to a meeting at the non-profit Cold Spring Harbor Laboratory in New York.

"I remember at the time being just completely stunned that she was somewhere between brave enough and crazy enough and because it was way, way, way beyond the technology available at that point," Berg said in a telephone interview.

Yonath found a way to freeze the ribosomes of bacteria and related organisms that thrive in the salty, airless conditions of the Dead Sea and make x-ray images of them.

It is the kind of work companies might shy away from, with a payoff decades in the future, and also arguably something American taxpayers should not have to fund. "But it was seen as certainly completely unique and something potentially so important that it should be funded," Berg said.

"These models are now used by scientists in order to develop new antibiotics, directly assisting the saving of lives and decreasing humanity's suffering," the academy said in its announcement on Wednesday.

"All three have used a method called X-ray crystallography to map the position for each and every one of the hundreds of thousands of atoms that make up the ribosome," the academy said.

Alfred Nobel, a Swedish industrialist who invented dynamite, established the Nobel Prizes in his will in 1895. The first awards were handed out six years later.

Each prize comes with a 10 million kronor [$1.4 million] purse, a diploma, a gold medal and an invitation to the prize ceremony in Stockholm on Dec. 10. The Peace Prize is handed out in Oslo.

Israeli physicist Yakir Aharonov lost the Nobel Prize for physics, despite predictions that he was likely to win. The committee awarded the the physics prize to engineers who developed the mechanism used in digital photography, preferring to award the prize to practical technology that could be used on a daily basis rather than the theoretical physics which Aharonov focused on.

The last Israeli to receive a Nobel Prize was Yisrael Robert Aumann, who was awarded the prize in economics in 2005 for his work on conflict and cooperation through game-theory analysis. He shared the prize with Thomas Schelling.