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Thomas A. Steitz, Nobel Prize winner for chemistry for mapping the structure of ribosomes, molecular machines that translate genetic information into thousands of proteins essential to living matter, died on October 9 at his home in Branford , in Connecticut. .
According to a statement from Yale University, he was suffering from pancreatic cancer, where he was professor of molecular biophysics, biochemistry and chemistry and had been part of the faculty since 1970.
Recognized as one of the best biochemists of the late twentieth century, Dr. Steitz was a kind of atomic cartographer, who developed maps in three dimensions that showed the location of tens of thousands of atoms in complex molecules. His work has been attributed to the development of new antibiotics, but on a more fundamental level they have highlighted the "central dogma" of molecular biology.
First declared by co-discoverer of DNA Francis Crick in 1958, dogma – a fundamental principle in the field – considers that genetic information passes from DNA to RNA and from RNA to proteins. The latter, long amino acid chains, play a vital role in all aspects of life, carrying molecules, providing structural support for cells, transmitting signals through tissues, effecting chemical reactions and combating viruses. pathogens such as viruses and bacteria.
While the general concept of dogma had long been established, Dr. Steitz and other researchers took decades into the details, using new computer-based technologies to discover the structures and functions of individual molecules. Their main technique was X-ray crystallography, a method in which molecules are crystallized and bombarded with X-rays, giving pointillist portraits that reveal the location of each atom.
Dr. Steitz worked on the reverse transcriptase of the HIV enzyme before turning to ribosomes in the 1990s, with some trepidation. If DNA is a model for life, the ribosome is a plant, the last stage of a process by which genetic information is transcribed from DNA to RNA, transmitted to one of many ribosomes. a cell and translated into proteins.
Steitz and Sidney Altman, an associate professor at Yale University, 1989 Nobel Laureate in Chemistry. (Douglas Healey / AP)
And this cell factory, like its synthetic counterpart, is imposing. A ribosome is composed of two subunits, and the largest section – which generates protein, and on which Dr. Steitz focused on his research – is about 50 times larger than an average enzyme .
Dr. Steitz's work resulted in the publication of two articles in a In the August 2000 issue of Science, in which he and his colleagues at Yale (including chemist Peter Moore) reported having discovered the structure of the large subunit of the ribosome, up to positions of 100,000 atoms .
"I think we were amazed at every step by the overwhelming complexity of ribosome folding by RNA," said Dr. Steitz in an interview with Yale's press office. "But I think the most surprising observation was that the proteins were included in the RNA helices, penetrating inside the ribosome like tentacles."
His articles were published at about the same time as related work by Venkatraman Ramakrishnan of the MRC Molecular Biology Laboratory in Cambridge, England; and Ada E. Yonath of the Weizmann Scientific Institute in Rehovot, Israel. The three scientists were awarded the Nobel Prize in Chemistry in 2009, when the committee honored them for discovering "what the ribosome looks like and how it works at the atomic level".
Because many antibiotics work by waving bacterial ribosomes, causing the death of pathogens, their work has been recognized as having paved the way for the development of new drugs that can fight against antibiotic-resistant bacteria. To this end, Dr. Steitz has partnered with two of his collaborators at Yale, Moore and William L. Jorgensen, to create Rib-X Pharmaceuticals, now known as Melinta Therapeutics.
"It can be difficult for those who entered the field of ribosomes after 2000 to understand what it was like to work on protein synthesis in Bad Old Days, without being informed by an accurate understanding of the protein." ribosome architecture, "said Moore in an email. "Before 2000, we were blind, but we could now see. Tom was one of the pioneers to have made this transformation possible.
The eldest of five children, Thomas Arthur Steitz was born in Milwaukee on August 23, 1940 and grew up in Wauwatosa, nearby. His father was a lawyer who worked as a trustee at the Milwaukee County Hospital and his mother was a housewife.
In an autobiographical essay published on the Nobel Prize website, he wrote that he was initially a poor student who cared little about grades, at least until his mother "applied the" board of education At the "seat of knowledge" – my first and last spanking. "
He then developed an aptitude for workshop tools (a skill that he said has served him well in the lab), as well as a keen interest in music, official saxophone competitions and the creation of A big band dance group in high school. "I seriously considered becoming a musician," said Dr. Steitz, "but then I concluded that I could make music as a hobby if I was studying science, but that I could not do science as a hobby if I gave it to music. "
Dr. Steitz studied molecular biology and biochemistry under the direction of William N. Lipscomb Jr. in 1976 at Lawrence College, Appleton, Wisconsin. At Harvard University, he won the Nobel Prize in Chemistry for research on collage.
Dr. Steitz obtained his Ph.D. from Harvard in 1966 and was married the same year to Joan Argetsinger, a biochemist colleague with whom he trained a couple of scientists. She had worked with Crick and James Watson and explained how long strands of RNA were "read" by ribosomes and translated into proteins.
The two researchers were professors at Yale and worked as investigators at the Howard Hughes Medical Institute in Chevy Chase, Md. Joan A. Steitz, received the Lasker-Koshland Award for outstanding achievements in the medical sciences several weeks before the death of the Dr. Steitz.
In addition to his wife of 52 years in Branford, the survivors include a son, Jon Steitz, a consultant and former minor baseball pitcher living in San Francisco, and two grandchildren.
Although Mr. Steitz grew up on a flat Midwestern site and did not leave the area until college, when he took his first flight to attend a conference on biochemistry at the Massachusetts Institute of Technology, he loved alpine metaphors and also love skiing.
His research on ribosomes, he once told the Milwaukee Journal Sentinel, "looked like a climb up a mountain. It looks very hard to stay up. Describing the ribosome, he told the Yale Press Office, was "like climbing Mount Everest or a four-minute run."
Indeed, in his essay on the Nobel Prize, Mr. Steitz wrote that he and his wife joined their "RNA-centered friends" on regular family ski trips, escaping from the laboratory for teach their children to ski on more or less black trails. As it should be, these trips bore a name evoking the cell site that Mr. Steitz came to master: "Riboski".
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