Thomas A. Steitz, Ph.D., Sterling Professor of Molecular Biophysics and Biochemistry, professor of chemistry and a Howard Hughes Medical Institute investigator, was among five scientists honored in April with the 2007 Gairdner International Award to recognize their contributions to medical science. The Gairdner Foundation honored Steitz and Harry F. Noller, Ph.D., of the University of California, Santa Cruz, for pioneering work that led to the identification of the detailed structure and function of the ribosome, the subcellular structure in which proteins are synthesized. Steitz and Noller identified that RNA-catalyzed reactions are critical, and their work explains how many antibiotics operate and how new ones can be developed.

Steitz uses X-ray crystallography and molecular biology techniques to establish the structures and mechanisms of the proteins and nucleic acids involved in gene expression, replication and recombination. In 2000, Steitz and colleagues published two articles in the journal Science in which they unveiled the basic structure of the ribosome. Their work provided the first unequivocal proof that the ribosome is a ribozyme, an RNA enzyme. Steitz and his colleagues used a high-energy X-ray beam to probe fragile crystals of RNA and protein and produce detailed images of the ribosome, where amino acids are linked to form chainlike proteins.

In more recent experiments, Steitz and his team have been studying antibiotic resistance. Their research has shown how the main target of antibiotics in bacterial cells becomes resistant to some medications. The findings are already leading to new experimental antibiotics that are being engineered to circumvent resistance, which is a major worldwide health problem.

Each Gairdner awardee will receive $30,000 in October in Toronto. The awardees are chosen by two advisory committees made up of leading medical scientists from Canada and around the world.

According to the Gairdner Foundation, 68 of the 283 scientists who have received the award in the past 48 years have gone on to win the Nobel Prize. Last year, the award went to two Yale scientists. Joan A. Steitz, Ph.D., Sterling Professor of Molecular Biophysics and Biochemistry and a Howard Hughes Medical Institute investigator,was honored for her discovery of snRNPs, complexes of protein and RNA that edit and splice other RNA strands to form messenger RNA, the genetic recipe used by the cell’s protein-making machinery. Thomas D. Pollard, M.D., chair and Sterling Professor of Molecular, Cellular and Developmental Biology, was recognized along with his colleague Alan Hall, Ph.D., of Memorial Sloan-Kettering Cancer Center in New York, for discovering the molecular basis of cellular motility and the mechanism of its regulation. In 2004, Arthur L. Horwich, M.D., HS ’78, the Eugene Higgins Professor of Genetics and Pediatrics and a Howard Hughes Medical Institute investigator, was honored for his findings on protein folding and its relevance to neurodegenerative diseases.