Grunberg-Manago was born into a family of artists who adhered to the teachings of the Swiss educational reformer Johann Pestalozzi. When she was 9 months old, her parents emigrated from the Soviet Union to France. Grunberg-Manago studied biochemistry and, in 1955, while working with Spanish-America biochemist Severo Ochoa, she discovered the first nucleic-acid-synthesizing enzyme. Initially, everyone thought the new enzyme was an RNA polymerase used by E. coli cells to make long chains of RNA from separate nucleotides. But although the new enzyme could link a few nucleotides together, the reaction was highly reversible and it later became clear that the enzyme, polynucleotide phosphorylase, usually catalyzes the breakdown of RNA, not its synthesis.
Nonetheless, the enzyme was extraordinarily useful and important. Almost immediately, Marshall Nirenberg and Heinrich J. Matthei put it to use to form the first three-nucleotide RNA codons, which coded for the amino acid phenylalanine. This first step in cracking the genetic code entirely depended on the availability of Grunberg-Manago’s enzyme.
Grunberg-Manago was the first woman to direct the International Union of Biochemistry, and she was also president of the French Academy of Sciences from 1995 to 1996. She is emeritus director of research at CNRS, France’s National Center for Scientific Research, and a member of the United States National Academy of Sciences.