Nicholas (Nick) R. Cozzarelli 1938–2006

from complications of treatment for Burkitt's lymphoma. Nick was a charismatic and passionate scientist, who spent his whole research career working and thinking about DNA. A mechanistic biochemist by training, he had an uncanny talent for " letting the DNA do the talking, " that is, he used the DNA substrate to provide insights into mechanisms of DNA processing enzymes. The son of a poor immigrant family from Italy, Nick grew up in New Jersey. It was impressed on him from his earliest years that education was the key to success. He originally intended to become a lawyer and went to Princeton University, but his interests shifted to medicine. He graduated in biology (1960) and went to Yale University Medical School for a year (but could not stomach autopsies). He obtained his PhD in biochemistry from Harvard University in 1966, did his postdoc-toral research at Stanford University Medical School (with Arthur Kornberg on DNA ligases), and in 1968 established his own lab in the Department of Biochemistry at the University of Chicago. In 1982 he went to the University of Cali-fornia, Berkeley, where he chaired the Department of Molecular Biology from 1986 to 1989. Elected to the National Academy of Sciences in 1989, Nick became Editor in Chief of the Academy's flag-ship publication, Proceedings of the National Academy of Sciences (PNAS). Under his stewardship, the impact of PNAS increased so that it became one of the most prestigious and accessible scientific journals. Nick was a champion of open-access publishing and made PNAS one of the first open-access journals. He also served on the board of Public Library of Science (PLoS) Biology. In his own research, Nick was not only passionate but also intensely rigorous. He set the very highest standards for himself and others. He had a natural gift for seeing the important question and for squeezing much more information and insight out of data than most scientists thought was possible. After taking up his first faculty position at the University of Chi-cago, he started to study the enzymes involved in DNA replication in Bacillus subtilis. Although this made for good biochemistry, it smacked of repeating Arthur Kornberg's pioneering work but in a different bacterium. It was while writing a review on inhibitors of DNA replication in 1977 that Nick decided to investigate new drugs that block DNA replication without disturbing the DNA polymeriza-tion machinery. This led to the startling …