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Erwin Chargaff was born on 11 August 1905 to Jewish family in Czernowitz, Duchy ofBukovina, Austria-Hungary, which is now Chernivtsi, Ukraine. He graduated from high school at the Maximilian Gymnasium in Vienna and proceededto the University of Vienna. In 1928 he obtained a doctoral degree in chemistry after havingwritten a thesis under the supervision of Fritz Feigl at Spath’s Institute. He went to the UnitedStates in 1928 as a Milton Campbell research fellow at Yale University. He stayed until 1930,when he went to the University of Berlin as an assistant in the public health department. In 1933he transferred to the Pasteur Institute in Paris, and in 1935 he returned to the United States tobecome an assistant professor of biochemistry at Columbia University. He became a fullprofessor 17 years later and was chairman of the department from 1970 to 1974, when hebecame an emeritus professor of biochemistry.
Chargaff discovered two rules that helped lead to the discovery of the double helixstructure of DNA. The first rule was that in DNA the number of guanine units is equal to the number ofcytosine units, and the number of adenine units is equal to the number of thymine units. This hinted at the base pair makeup of DNA. The second rule was that the relative amounts of guanine, cytosine, adenine and thyminebases vary from one species to another. This hinted that DNA rather than protein could be thegenetic material.What Chargaff discovered was that adenine and thymine exist in equal proportions in allorganisms, as do cytosine and guanine, but that the proportions between the two pairs differdepending on the organism. These relationships are usually expressed as follows: purines(adenine + guanine) equal pyrimidines (cytosine + thymine); adenine equals thymine; andguanine equals cytosine.
Chargaff drew the conclusion that it is in fact the DNA in the nucleus ofthe cell that carries genetic information rather than the protein. His argument was that, whilethere were only four different nucleic acids, as opposed to 20 proteins, the number of differentproportions in which they could exist and the many different orders in which they could bepresent on the DNA strand provided a basis of complexity sufficient for the formation of genes.He also realized that there must be as many different types of DNA molecules as there arespecies. Chargaff’s conclusions revolutionized the biological sciences. One extremely importantresult of his discovery was that it helped James D. Watson and Francis Crick of the CavendishLaboratory in Cambridge, England, in their determination of the structure of DNA. They reasoned that because adenine and thymine always exist in the same proportion, they mustalways bond together, and similarly for cytosine and guanine. This conclusion led them topropose a double helix structure for DNA, for which they won the Nobel Prize in 1952. Theirmodel showed DNA as consisting of two strands of sugar and phosphate (alternating on eachstrand) with the pyrimidine and purine bases attached to each sugar component and bonding thetwo strands together.
Though his main interest lay in the living cell and he liked to think of himself as a naturalistphilosopher, Chargaff did research in many areas of biochemistry. He did a lot of work with lipids,the molecules that form fats, and in particular studied the role of lipid-protein complexes in themetabolism. He also did work with thromboplastic protein, the enzyme (biological catalyst) thatinitiates blood coagulation.Chargaff received honorary degrees from Columbia University and the University ofBasel in 1976. A member of many scientific societies including the National Academy ofScience, he was a visiting professor in numerous universities around the world. He also wonmany awards, including the Pasteur medal in 1949, the Charles Leopold Mayer Prize from theAcademy of Science in Paris in 1963, and the Gregor Mendel medal in 1973.
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