Shimomura was born in northern Kyoto in 1928 and studied in Nagasaki, where he survived the Aug. 9, 1945, U.S. atomic bombing at age 16. His high school education was cut short during World War II as he was mobilized to work at a munitions factory.
He eventually earned chemistry degree in 1951 from Nagasaki College of Pharmacy.
In 1960 he moved to Princeton University, where he isolated the protein in samples of thousands of jellyfish taken from the U.S. West Coast, often with the help of his wife Akemi.
The protein known as Green Fluorescent Protein lets off a glow when it is illuminated with ultraviolet light and has become a key tool in studying biological processes in cells.
Shimomura was based in the U.S., but had moved back to Nagasaki to be close to his relatives, Nagasaki University officials said.
The devastation from the atomic bomb that killed 70,000 in Nagasaki, left a lasting impression on Shimomura and he often mentioned his experience and called for nuclear weapons ban in his lectures later in life.