Roger D Kornberg of the United States won this year's Nobel Prize for Chemistry, it was announced in Stockholm on Wednesday.
The Royal Swedish Academy of Sciences cited his studies of the molecular basis of eukaryotic transcription in awarding him the 10 million kronor (1.37 million dollar) prize.
Eukaryotes were described the academy as organisms that have a well-defined nucleus.
Transcription is the copying process when information or instructions from genes are transferred to the outer part of the cells, and for the production of protein production. Proteins construct the organism and its function, the academy said.
Minutes after being notified of the award, Kornberg who is Professor of Medicine at Stanford University, said on the phone at 3 am in California: "I am very grateful to be one of at least 50 people who have been working on this. There were Swedes, French and German colleagues. The majority come from Europe.
"The call from Stockholm was so stunning that I am still shaking. I had been awake for almost 48 hours because of travelling from the European time zone," he added.
Kornberg is the second member of his family to win the prestigious award. In 1959 his father, Arthur Kornberg, was awarded the Nobel Prize for Medicine for discoveries on how genetic information is transferred from one DNA molecule to another.
The chemistry prize was the third of the awards announced this year. Earlier, two Americans won the medicine prize and two Americans shared the physics prize.
Kornberg said the reason the US has swept the prizes: "It's the unprecedented magnitude of public support for sciences in the US. And it is simply the size of the scientific establishment," he said.
DPA