CHARGAFF, ERWIN

CHARGAFF, ERWIN (1905–2002), U.S. biochemist. Chargaff was born in Czernowitz, then Austro-Hungary, and gained a doctorate in chemistry from the University of Vienna (1928). He held postdoctoral research posts consecutively at the Universities of Yale, Vienna, and Berlin, and at the Institut Pasteur in Paris before awareness of the Nazi menace led him to immigrate to the U.S. (1934). He joined the Department of Biochemistry of Columbia University's College of Physicians and Surgeons, where he became professor, department chairman, and professor emeritus before retiring in 1992. Early in his research career Chargaff made major contributions to characterizing the proteins involved in blood clotting. In 1944 he accepted Avery's evidence that DNA in a bacterium determined its hereditary characteristics. He reasoned that genetic differences in DNAs must be attributable to chemical differences in these molecules. He established that in all species of DNA tested the molar ratios of purines to pyrimidines, of adenine to thymine, and of guanine to cytosine is virtually 1.0. These "Chargaff rules" were a vital contribution to the elucidation of the structure of DNA by Watson, Crick, and Wilkins and the role of base pairing in gene copying. Subsequently Chargaff was embittered that his contributions to solving arguably the most important problem in biology received inadequate recognition, not least from the proponents of the double helix model. As his skills as an analytical chemist became increasingly irrelevant to the development of molecular biology, he turned instead to his great literary skills, which he used to express prophetic warnings on the evils of unbridled biotechnology. Nevertheless his contributions are now recognized and his many honors included election to the U.S. National Academy of Sciences (1965) and the National Medal of Science (1974). (Michael Denman (2nd ed.)