Sweden's Tomas Lindahl, Paul Modrich of the United States and Aziz Sancar, a Turkish-American, have won the 2015 Nobel Chemistry Prize for work on how cells repair damaged DNA.
The three opened a dazzling frontier in medicine by unveiling how the body repairs DNA mutations that can cause sickness and contribute to ageing, the Nobel jury said on Wednesday (local time).
"Their systematic work has made a decisive contribution to the understanding of how the living cell functions, as well as providing knowledge about the molecular causes of several hereditary diseases and about mechanisms behind both cancer development and ageing," the panel said.
DNA – deoxyribonucleic acid – is the chemical code for making and sustaining life.
Cells divide, or replicate, billions of times through our lifetime.
Molecular machines seek to copy the code perfectly, but random slipups in their work can cause the daughter cells to die or malfunction. DNA can also be damaged by strong sunlight and other environmental factors.
But there is a swarm of proteins – a molecular repair kit – designed to monitor the process. It proof-reads the code and repairs damage.
The three were lauded for mapping these processes, starting with Lindahl, who identified so-called repair enzymes – the basics in the toolbox.
Sancar discovered the mechanisms used by cells to fix damage by ultraviolet radiation.
Modrich laid bare a complex DNA-mending process called mismatch repair.
"The basic research carried out by the 2015 Nobel laureates in chemistry has not only deepened our knowledge of how we function, but could also lead to the development of life-saving treatments," the Nobel committee said.
With cells able to repair themselves, one could ponder the dizzying possibility that humans could go on living forever.
"No, I don't believe in eternal life," Lindahl, who is based in Britain, told reporters by telephone at the prize announcement.
He said scientists were increasingly turning their attention away from curing diseases such as cancer and instead looking for chronic treatments.
"We are getting away a little bit [from] trying to find a cure for everything, and convert diseases to something we can live with," the 77-year-old said.
"It's difficult to cure diabetes but we have good ways of treating diabetic patients, and I think with regard to DNA damage that will be an increasingly important aspect."
It is the seventh time DNA research has been honoured with a Nobel prize. The first was in 1962, for the discovery of the structure of DNA.
Lindahl, Modrich and Sancar share the prize sum of eight million Swedish kronor (around NZ$1.8 million).
Modrich was born in 1946 and grew up in a small town in northern New Mexico, which instilled in him a love of the natural world.
"There was huge biological diversity around me," he said in a statement.
"Within five miles, the ecology can change dramatically – it was very thought provoking."
Sancar, 69, was born in the small Turkish town of Savur. He could have become a professional football player – Turkey's national junior team courted him to become their goalkeeper – but he chose to focus on his academic studies instead.
After working as a doctor in the countryside, he resumed his biochemistry studies at the age of 27, and then went to the University of Texas in Dallas.
He is now a professor of biochemistry and biochemics at University of North Carolina in the US.
He told the Nobel Foundation he was stunned by his win.
"I wasn't expecting it at all. I was very surprised."