RNA

Phoebus Aaron eodore Levene (Figure 4.1) studied both RNA and DNA, and con-tributed key insights into the structures of both biopolymers. When Levene began his research at the Rockefeller Institute for Medical Research, precipitation techniques had been used to isolate two dierent types of nucleic acids-one from yeast and the other from calf thymus. In 1909, Levene showed that the carbohydrate in the nucleic acids isolated from yeast was the pentose sugar ribose, correctly identifying the material from yeast as RNA. Twenty years later, Levene also correctly identied the equivalent carbohydrate in material extracted from calf thymus as deoxyribose. Additionally, Levene deduced key structural elements of nucleic acids; for example, he coined the term “nucleoside” to describe a carbohydrate linked through a glycosidic bond to the base of a nucleic acid. With tour de force experimentation, he also discovered that the phosphodiesters link to the 3ʹ and 5ʹ carbons of the nucleic acid carbohydrate. us, Levene earned a spot in the pantheon of chemical biology through key insights into the chemical structures of RNA and DNA.