Heinz Fraenkel-Conrat Biography

Heinz Fraenkel-Conrat is an internationally known German-born biochemist who became a naturalized citizen of the United States. The majority of his research, and the studies for which he is best known, was conducted at the University of Berkeley, California. Fraenkel-Conrat's research helped advance the study of viruses. He determined that under certain conditions, a virus could be separated into its component parts. These studies revealed both the virus's infective agent and its method of replication. Fraenkel-Conrat's research inspired numerous studies of viruses, which proved useful in the explanation of molecular biological processes such as replication and mutation.

Fraenkel-Conrat was born July 29, 1910, in Breslau, Germany (now Wrocllaw, Poland) to Ludwig Fraenkel, a gynecologist who was famous for his discoveries concerning mammalian ovulation, and Lili Conrat Fraenkel. Fraenkel-Conrat was educated in Munich, Vienna, Geneva, and at the University of Breslau, where he received his M.D. in 1933. He left Germany when Adolf Hitler and his Nazi party came into power. In 1936, Fraenkel-Conrat obtained his Ph.D. in biochemistry from the University of Edinburgh, Scotland, for studies on ergot alkaloids and thiamine. He subsequently came to the United States and studied a type of enzyme at the Rockefeller Institute for Medical Research in New York. Fraenkel-Conrat unexpectedly discovered that enzymes formed peptide bonds, which, in turn, form the building blocks of proteins. Fraenkel-Conrat next joined his brother-in-law, K. H. Slotta, as a research associate at the Instituto Butantan at Sao Paulo, Brazil, where he began to study the components of snake venoms. The work resulted in the isolation of a protein from rattlesnake venom that acted as a neurotoxic and also destroyed red blood cells.

Fraenkel-Conrat left Brazil and returned to the United States, becoming a naturalized citizen in 1941. He became a member of the H. M. Evans Institute of Experimental Biology at the Berkeley Campus of the University of California in 1938. For more than ten years, his research involved purifying hormones, particularly follicle-stimulating hormones, and studying how structural changes effected hormonal activity. Some of this work was carried out at the Western Regional Research Laboratory of the U.S. Department of Agriculture, where he worked from 1938 to 1942, first as an associate chemist and then later as a chemist. His work at this time also focused on modifying protein groups. Fraenkel-Conrat and his co-workers documented how modifying a protein's structure changed its function. Several of their techniques were later used by others studying proteins.

Fraenkel-Conrat joined the virus laboratory of the University of California, Berkeley, in 1952. In 1960, using techniques similar to those in his protein work, he and his collaborators were able to determine the complete amino acid sequence--consisting of 158 amino acid residues--of the tobacco mosaic virus (TMV), making it the biggest protein of known structure at the time. Several years before Fraenkel- Conrat's virus research, scientists had determined that viruses contained a protein shell and nucleic acid the latter was believed to carry the virus's genetic information. From his studies of protein structure, Fraenkel-Conrat began further studies with the tobacco mosaic virus. He developed techniques that enabled him to gently separate the protein material from the nucleic acid, in the form of ribonucleic acid (RNA), without seriously damaging either part. He then recombined the protein and nucleic acid. If both molecules were intact, the particles rejoined and were once more infective.

Fraenkel-Conrat's subsequent research proved to be his most distinguished work. Continuing his experiments, he showed that when the two substances were separated, the protein coat had no infective properties but the ribonucleic acid still was somewhat infective. Subsequent studies showed that the protein shell was needed to get the nucleic acid, which carried the virus's genetic material, into a host cell. Once inside the cell, the nucleic acid took over the host cell's own genetic material, deoxyribonucleic acid (DNA), and began reproducing itself, making not only more infective nucleic acid but compatible protein coatings as well. This study provided definitive proof that RNA can act like DNA as the genetic blueprint for cell reproduction. Fraenkel-Conrat continued to study RNA and, along with B. Singer and other colleagues, developed new methods for stabilizing the acid for better structural studies.

From 1952 until 1958, Fraenkel-Conrat was a professor of virology at the University of California, Berkeley; he later became a professor of molecular biology. In 1968, his research emphasis concentrated on how RNA was translated in viruses and how viruses replicated this material. In 1982, when he retired, he became emeritus professor of molecular biology. For his contributions to the field of molecular biology, he was honored by a Lasker Award, also receiving the first California Scientist of the Year Award in 1958. He was also a member of the National Academy of Sciences. After retiring, his interests remained with the field of virology and he wrote a number of virology texts. For close to ten years, Fraenkel-Conrat was a contributing editor of the journal Comprehensive Virology, starting in 1973.

Fraenkel-Conrat died on April 10, 1999.