Erwin Chargaff, who died on June 20th aged 96, was one of the giants of the world of biochemistry. He did pioneering work in several fields; hence, his absence from the roll of Nobel prizewinners remained something of an enigma.
He was best known for his work in genetics, involving research into the chemical composition of DNA. Erwin Chargaff's data, along with that of Rosalind Franklin's X-ray diffraction pictures of DNA, provided the groundwork for the greatest discovery of 20th-century biology, by James Watson and Francis Crick, when they solved the riddle of heredity and showed how genetic inheritance could pass from one generation to the next through the double-helix structure of DNA.
Erwin Chargaff's crucial finding was to detect the regularity with which the four chemical units of DNA, called bases and known by the letters A, C, G and T, occurred in pairs. The full significance of the finding, in pointing to a coding system in the hereditary material of living organisms, escaped him - a failure that Watson and Crick repaired when they studied the structure of DNA.
The discovery of what became widely known as base-pairing carried weight because Erwin Chargaff was a hugely respected experimental scientist. Watson has said that the acceptance of Erwin Chargaff's findings by other scientists was almost as important as the discovery itself, and that the base-pair system was an essential clue in deciphering the structure of DNA. Although he imagined that he and Crick could have come up with the answer, Watson thought that no one would have believed it.
Among his claims to scientific fame, Erwin Chargaff disproved the tetranucleotide hypothesis and demonstrated the existence of a large number of different DNA species. He also did research on blood coagulation, lipids and lipoproteins, metabolism of amino acids and inositol, and biosynthesis of phosphotransferases.
Erwin Chargaff was born on August 11th, 1905, in Czernowitz, a provincial capital of the Austro-Hungarian empire (now in Ukraine). His father was a banker; his mother disappeared after being deported in 1943. He studied chemistry at the University of Vienna, where he obtained his Ph.D in 1928, and then spent two years at Yale, studying the tuberculosis bacterium and devising methods of isolating some of the unusual fatty molecules it contained.
At Berlin University from 1930 to 1933, he extended his research into bacterial lipids; he spent two years at the Pasteur Institute in Paris; and, in 1935, he settled at Columbia University, New York, where, initially, he worked on plant chromoproteins.
It was in 1944 that Erwin Chargaff read the Nobel prizewinning research of Oswald Avery, who had identified DNA as the hereditary material. Erwin Chargaff promptly turned his laboratory to the study of DNA and its four chemical bases - adenine, cytosine, guanine and thymine - using a refinement of the chromatography technique of two British scientists, John Martin and Richard Synge.
He found a striking regularity of the base composition of DNA; from whatever plant or animal tissue he used, the amounts of adenine and thymine were almost the same, as were the amounts of cytosine and guanine. He published the result, but made little progress in interpreting the reason for the regularity in which adenine on one of the DNA molecule's two strands was always paired with thymine on the other, as was cytosine with guanine.
Erwin Chargaff discussed the results at a tetchy meeting with Watson and Crick in May 1952, and later told Horace Judson, the historian of the discovery of DNA, that "they impressed me by their extreme ignorance". Indeed, he believed that the pair's discovery came about as a consequence of this conversation - a claim dismissed by Judson, who in an appendix to a new edition of his book, The Eighth Day Of Creation (1996), observed that Watson and Crick had not, at that time, hit on the concept of base pairing, nor had Erwin Chargaff alluded to it in his publications.
Erwin Chargaff later became a forceful, if lonely, critic of molecular biology, accusing scientists of "practising biology without a licence" when they learned to move genes from one organism to another.
Always the European, he found much in American life to criticise, despite his long and productive tenure at Columbia. He cherished the outsider's role, modelling his sardonic view of the world on the writings of Karl Kraus, the Viennese satirist, whom he described as his only teacher. When people told Erwin Chargaff he was a misfit, he agreed.
A professor from 1952 onwards, he retired to emeritus status in 1974, though his time at Columbia did not end happily. He was locked out of his office and exiled to a distant building. When a new chairman of biochemistry invited him back, Erwin Chargaff declined, choosing to add that, in the event of his death, "my simple request is: I do not want to be remembered by the university".
His only son, Thomas, survives him.
Erwin Chargaff: born 1905; died, June 2002