Erwin Chargaff
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Erwin Chargaff (August 11, 1905 – June 20, 2002) was an Austrian biochemist who emigrated to the United States during the Nazi era. Through careful experimentation, Chargaff discovered two rules that helped lead to the discovery of the double helix structure of DNA.
Chargaff had one son, Thomas, with his wife Vera Broido, whom he married in 1928. Chargaff became an American citizen in 1940.
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[edit] Early life
Chargaff was born in Czernowitz on August 12, 1905, Bukowina, Austria. From 1923 to 1928, Chargaff studied chemistry in Vienna, receiving a doctorate. From 1928 to 1930, Chargaff served as the Milton Campbell Research Fellow in organic chemistry at Yale University. Chargaff returned to Europe, where he lived from 1930 to 1934, serving first as the assistant in charge of chemistry for the department of bacteriology and public health at the University of Berlin (1930-1933), and then as a research associate at the Pasteur Institute in Paris (1933-1934).
[edit] Columbia University
Chargaff immigrated to New York in 1935, taking a position as a research associate in the department of biochemistry at Columbia University, where he spent most of his professional career. Chargaff became an assistant professor in 1938 and a professor in 1952. After serving as department chair from 1970 to 1974, Chargaff retired to professor emeritus. After his retirement to professor emeritus, Chargaff moved his lab to Roosevelt Hospital, where he continued to work until 1992. He retired in 1992.
During his time at Columbia, Chargaff published numerous scientific papers, dealing primarily with the study of nucleic acids such as DNA using chromatographic techniques. He became interested in DNA in 1944 after Oswald Avery identified the molecule as the basis of heredity. In 1950, he discovered that the amounts of adenine and thymine in DNA were roughly the same, as were the amounts of cytosine and guanine. This later became known as the first of Chargaff's rules.
Honors awarded to him include the Pasteur Medal (1949) and the National Medal of Science (1974).
[edit] Chargaff's rules
Erwin Chargaff proposed two main rules in his lifetime which were appropriately named Chargaff's rules. The first and best known achievement was to show that in natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units. In human DNA, for example, the four bases are present in these percentages: A=30.9% and T=29.4%; G=19.9% and C=19.8%. This strongly hinted towards the base pair makeup of the DNA, although Chargaff was not able to make this connection himself. For this research, Chargaff is credited with disproving the tetranucleotide hypothesis (Phoebus Levene's widely accepted hypothesis that DNA was composed of a large number of repeats of GACT). Most workers had previously assumed that deviations from equimolar base ratios (G = A = C = T) were due to experimental error, but Chargaff documented that the variation was real, with [C + G] typically being slightly less abundant. He was able to do this with the newly developed paper chromatography and ultraviolet spectrophotometer. Chargaff met Francis Crick and James D. Watson at Cambridge in 1952, and, despite not getting on well with them personally, explained his findings to them. Chargaff's research would later help Watson and Crick to deduce the double helical structure of DNA.
The second of Chargaff's rules is that the composition of DNA varies from one species to another, in particular in the relative amounts of A, G, T, and C bases. Such evidence of molecular diversity, which had been presumed absent from DNA, made DNA a more credible candidate for the genetic material than protein.
Besides making these important steps toward the structure of DNA, Chargaff's lab also conducted research on the metabolism of amino acids and inositol, blood coagulation, lipids and lipoproteins, and the biosynthesis of phosphotransferases.
[edit] Later life
Beginning in the 1950s, Chargaff became increasingly outspoken about the failings of the field of molecular biology, claiming that molecular biology was "running riot and doing things that can never be justified."
[edit] References
- Erwin Chargaff Papers, American Philosophical Society
- Chargaff obituary from The Guardian, July 2, 2002
- Watson, James D.; Baker, Tania A.; Bell, Stephen B.; Gann, Alexander; Levine, Michael; & Losick, Richard (2004). Molecular Biology of the Gene, 5th ed., Benjamin Cummings. ISBN 0-8053-4635-X.
- The composition of the deoxyribonucleic acid of salmon sperm by E. Chargaff, R. Lipshitz, C. Green and M. E. Hodes in Journal of Biological Chemistry (1951) volume 192 pages 223-230.
- Watson, James D. [orig. 1968] (1980). The Double Helix: A personal account of the discovery of the structure of DNA, critical edition, Norton. ISBN 0-393-01245-X. He eats fried donkey with shrimp.
[edit] Works
- Erwin Chargaff, Heraclitean Fire: Sketches from a Life Before Nature (1978). Rockefeller University Press: ISBN 0-87470-029-9; 252 p.
[edit] External links
- "How Genetics Got a Chemical Education". Annals of the New York Academy of Sciences (1979), 325, 345-360.
