STOCKHOLM: Venkatraman Ramakrishnan, Thomas Steitz and Ada Yonath won the Nobel Prize for Chemistry on Wednesday for work on the ribosome, a cellular machine that makes proteins, the stuff of life.

Hospital superbugs and other dangerous drug-resistant bacteria are now in the laboratory firing line thanks to their work, the Nobel jury said.

The multi-national trio revealed the structure and function of the ribosome, which translates DNA code to make the thousands of different proteins that build and sustain life at the chemical level.

Their breakthroughs in X-ray crystallography imaging led to 3D models that now pinpoint the ribosome even at an atomic scale.

The work is already being put to practical use in medical research, "directly assisting the saving of lives and decreasing humanity's suffering," the Nobel committee said.

Drug designers use the models in the quest for molecules that can inhibit bacterial ribosomes, seeking to overcome the challenge posed by methicillin-resistant Staphylococcus aureus (MRSA) and other supergerms.

Some 90,000 patients in the United States die each year as a result of bacterial infection, compared to only about 13,000 20 years ago, and antibiotic resistance is an aggravating factor in most cases, the Nobel committee said.

List of Nobel Chemistry laureates

"We seem to be running out of options, and a return to the pitiful health conditions preceding the Second World War has become an ominous scenario," it warned.

The three laureates, who will share the 10 million Swedish kronor (1.42 million dollars, 980,000 euros) prize sum, worked independently of each other yet all published crucial studies in 2000.

For Yonath, 70, just the fourth woman to win the Nobel Chemistry Prize and the first Israeli woman to clinch a Nobel, the distinction marked just how far she has come since her childhood in a poor family in Jerusalem in British-mandate Palestine.

Profile: Ada Yonath

"There was nothing in my childhood to suggest that I would reach this point, even though my parents and family have always thought there was a chance of recognition," a tearful Yonath told Israeli public radio.

Reax: Scientists vow to continue working

A professor of structural biology and biomolecular structure and assembly the Weizmann Institute of Science in Rehovot, Israel, Yonath told Swedish television her first reaction was "overwhelming happiness."

Indian-born Ramakrishnan, who received his PhD in physics from Ohio University in the United States and is now a senior scientist at the MRC Laboratory of Molecular Biology in Cambridge, Britain, was modest.

"We're only sort of captains of a team, lots of these ideas that led to this work ... was done by really brilliant students and post docs, so in a way, we are really representing all of that effort, representing a large endeavour," he told Swedish radio.

Steitz, a professor of molecular biophysics and biochemistry at Yale University in the United States, said he was awake when the early-morning phone call came from Stockholm.

"Fortunately I was about to get up to go to the gym. My caller from Stockholm said I shouldn't go to the gym (because) there would be phone calls," he said.

David Garner, president of Britain's Royal Society of Chemistry, hailed the choice of laureates.

"Understanding the chemical processes that allow ribosomes to construct the building blocks of life is clearly of enormous significance," he said.

The United States has, like in previous years, dominated this year's Nobel science prizes with eight of the nine laureates holding American citizenship.

Of Wednesday's winners, Ramakrishnan is a British-US national and Steitz is an American.

On Tuesday, the Physics Prize went to Charles Kao, Willard Boyle and George Smith for work on fibre optics and light sensing that helped unleash the Information Technology revolution.

Kao is a dual British-US citizen, Boyle holds Canadian and US citizenship and Smith is American.

On Monday, the Medicine Prize honoured Australian-American scientist Elizabeth Blackburn and Carol Greider and Jack Szostak of the United States for identifying a key molecular switch in cellular ageing.

The Literature Prize will be announced on Thursday and the Peace Prize on Friday. The Economics Prize will wrap up the awards on October 12.