Erwin Chargaff
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Erwin Chargaff (August 11, 1905 – June 20, 2002) was an Austrian biochemist. Through careful experimentation, Chargaff discovered two rules that helped lead to the discovery of the double helical structure of DNA.
Chargaff had one son, Thomas, with his wife Vera Broido, who he married in 1928. Chargaff became an American citizen in 1940.
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Early life
Chargaff was born in Czernowitz, 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).
Columbia University
Chargaff emigrated 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.
During his time at Columbia, Chargaff published numerous scientific papers, dealing primarily the study of nucleic acids such as DNA using chromatigraphic techniques. This research led to the discover of Chargaff's rules.
Chargaff's rules
Erwin Chargaff proposed two main rules in his lifetime which were appropiately 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 chromotography 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.
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."
After his retirement to professor emeritus in 1974, Chargaff moved his lab to Roosevelt Hospital, where he continued to work until 1992.
External links
- "How Genetics Got a Chemical Education" (http://crystal.biochem.queensu.ca/forsdyke/bioinfo1.htm). Annals of the New York Academy of Sciences (1979), 325, 345-360.
References
- Erwin Chargaff Papers (http://www.amphilsoc.org/library/mole/c/chargaff.htm), American Philosophical Society
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