The Royal Swedish Academy of Sciences said Venkatraman Ramakrishnan, Thomas Steitz and Israeli Ada Yonath's work on ribosomes has been fundamental to the scientific understanding of life. They will split the 10 million ($1.4 million award).
Yonath, 70, is the fourth woman to win the Nobel chemistry prize and the first since 1964, when Dorothy Crowfoot Hodgkin of Britain received the award.
"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."
Ribosomes are crucial to life because they produce the proteins that control the chemistry of plants, animals and humans. Working separately, the three laureates used a method called X-ray crystallography to pinpoint the positions of the hundreds of thousands of atoms that make up the ribosome.
Their three-dimensional models show how different antibiotics bind to ribosomes - an understanding that has helped other researchers develop new drugs to fight bacterial infections.
"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.
Many of today's antibiotics cure diseases by blocking the function of bacterial ribosomes, the citation said. "Without functional ribosomes, bacteria cannot survive. This is why ribosomes are such an important target for new antibiotics."
The work was published in 2000. While many Nobel winners are honored for joint work, this year's chemistry winners were competing with each other, award committee member Mans Ehrenberg said.
Their work builds on Charles Darwin's theory of evolution and, more directly, on the work done by James Watson, Francis Crick and Maurice Wilkins, who won the 1962 Nobel Prize in medicine for mapping DNA's double helix, the citation said.
In 2006, Roger D Kornberg won the Nobel Prize in chemistry for X-ray structures that showed how information is copied to messenger RNA molecules, which carry information from DNA to the ribosomes.
"Now, one of the last pieces of the puzzles has been added - understanding how proteins are made," said Professor Gunnar von Heijne of the Swedish Academy of Sciences, the chairman of the Nobel Committee for Chemistry."
Thomas Lane, president of the American Chemical Society, said the award was an example of how chemistry can improve people's lives.
"For me it's another example where chemistry is the central science for addressing some of these very big issues," he said. "You hear words like 'ribosome' and 'bacteria,' and you tend to think biology when in fact it's chemistry at work."
Indian-born Ramakrishnan, 57, is the senior scientist and group leader at the Structural Studies Division of the MRC Laboratory of Molecular Biology in Cambridge, England.
Ramakrishnan said that he wasn't convinced when he got the morning phone call from the academy.
"Well, you know, I thought it was an elaborate joke. I have friends who play practical jokes," Ramakrishnan told The Associated Press by telephone from his lab in Cambridge. "I complimented him on his Swedish accent."
Ramakrishnan described his work on ribosomes as an attempt to understand "this large molecular machine that takes information from genes and uses it to stitch together protein."
He said he and others had been using X-ray crystallography to build an "atomic picture of this enormous machine."
"Now we can start figure out how it does this complicated process," he said.
Steitz, a 69-year-old born in Milwaukee, is a professor of molecular biophysics and biochemistry at Yale University and attached to the Howard Hughes Medical Institute, both in New Haven, Connecticut.
Yonath is a professor of structural biology at the Weizmann Institute of Science in Rehovot, Israel, and the ninth Israeli to win a Nobel prize. She told Israel Radio she didn't think her gender played a role in the decision.
"It's true that a woman hasn't won since 1964. But I don't know what that means - does it mean that I'm the best woman since then? I don't think that gender played a role here," she said.
She had to end the interview abruptly because Israeli President Shimon Peres, a Nobel Peace prize laureate, was on the other line.
About Nobel Prizes
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 December 10. The Peace Prize is handed out in Oslo.
On Monday, three American scientists shared the Nobel Prize in medicine for discovering a key mechanism in the genetic operations of cells, an insight that has inspired new lines of research into cancer.
The physics prize on Tuesday was split between a Hong Kong-based scientist who helped develop fiber-optic cable and two Canadian and American researchers who invented the "eye" in digital cameras - technology that has revolutionized communications and science.
The literature and peace prize winners will be announced later this week and the economics announcement is set for Monday.