Thirty years ago yesterday, biochemists Arthur Kornberg and Mehran Goulian announced the creation of an artificial copy of DNA that was biologically active and could infect cells. The achievement opened the door to further studies of the molecular basis of heredity and new strategies to treat cancer and genetic diseases.
After Watson and Crick's 1953 discovery of DNA's chemical structure, Kornberg set out to synthesize a giant DNA molecule. Four years later, his group discovered an enzyme called DNA polymerase, which catalyzes new DNA strands from nucleic acid building blocks. With the help of this enzyme, Kornberg and Severo Ochoa synthesized inactive DNA molecules, a feat that earned them the Nobel Prize in physiology or medicine in 1959.
In 1966 Kornberg and Goulian discovered an enzyme called ligase that closes a DNA strand into a ring, a configuration that makes viral DNA infectious. The duo mixed in a test tube a viral DNA template, nucleic acids, DNA polymerase, and ligase. The resulting DNA molecule, representing the inner core of a virus, proved to be infectious.
[Source: Emily Mcmurray, Ed., Notable Twentieth Century Scientists (Gale Research Inc., ITP, 1995).]