An 18-year study that revealed the atomic structure of Earth's most abundant protein could lead to higher crop yields, better drugs to combat cancer and heart disease, and even more effective laundry detergents, scientists say.

The study by biochemist David Eisenberg of the University of California, Los Angeles, "is very significant work," said Dr. John Norvell, health science administrator at the National Institute of General Medical Sciences in Bethesda, Md."It will add a lot to the understanding of how these complex proteins work," and therefore may help researchers trying to design proteins to combat several diseases, including diabetes and cancer, Norvell said.

Eisenberg and his students published their study Friday in the journal Science. They spent 18 years bombarding crystals of the protein, named RuBisCO, with X-rays before they successfully produced computer images showing the three-dimensional arrangement of the 37,792 atoms in the protein, which ultimately sustains life by making every plant grow.

"Learning the structure of this protein will aid researchers who are hoping to increase crop yields" by altering the protein so it makes plants grow more quickly, said Eisenberg, a physical chemistry and molecular biology professor at UCLA.

RuBisCO stands for ribulose-1,5-bisphosphate carboxylase-oxygenase, a protein present in all green plants. It transforms carbon dioxide into sugar to start photosynthesis, the sunlight-aided process that makes plants grow.

"This protein is vital to all life," said retired UCLA plant physiologist Sam Wildman, who discovered RuBisCO in 1947. "We all depend on photosynthesis (for food). This protein performs a key function in photosynthesis. By knowing the structure, clever people like Eisenberg can plot how to modify the structure so the plant would make more matter, which is what we eat."

The study also is another step in helping scientists learn the rules by which amino acids, the building blocks of life, form complex proteins.

Such knowledge eventually may help researchers design proteins to kill cancers, destroy blood clots that cause heart attacks, degrade toxic wastes and even make better laundry detergents.

Plants on Earth produce 1.1 tons of RuBisCO each second, or 35 million tons per year, Eisenberg said. RuBisCO, which is 10,000 times smaller than the width of a human hair, constitutes half the soluble protein in all plants, making it the most abundant protein on Earth.