Steitz, Thomas Arthur, 1940–, American biophysicist and biochemist, Ph.D. Harvard, 1966. Steitz has been a professor at Yale since 1970 and a researcher and professor at the Howard Hughes Medical Institute since 1986. He was a co-recipient with Venkatraman Ramakrishnan and Ada Yonath of the 2009 Nobel Prize in Chemistry for their studies demonstrating the structure and function of the ribosome, which translates the information encoded in DNA into protein sequences (see cell, in biology; nucleic acid). The researchers used X-ray crystallography to map the position of each of the hundreds of thousands of atoms that make up the ribosome, and they developed three-dimensional models showing how various antibiotics bind to the ribosome. Their work made fundamental contributions to the scientific understanding of life and to the development of antibiotics, many of which work by interfering with the functioning of bacterial ribosomes.