Cech, << chehk >> Thomas Robert (1947-…), an American biochemist, researched into the chemical properties of ribonucleic acid (RNA). In the early 1980’s, he discovered that a particular type of RNA could catalyze (promote) chemical reactions in the cell without itself being used up. Among other things, this contributed to the understanding of how life itself could have begun. Cech received the Nobel Prize inchemistry in 1989, sharing the prize with Sidney Altman (see Altman, Sidney ).
Cech studied a particular one-celled organism called Tetrahymena. He chose it because of its unusual structure. In Tetrahymena, unlike most other organisms, the genes that produce molecules, made up of a type of RNA called ribosomal RNA (rRNA), are outside the nucleus, and so are more readily accessible. This material has to be copied thousands of times as part of the process of making rRNA. This copying happens so rapidly that Cech believed that another molecule was helping the process to happen—in other words, was acting as a catalyst. Cech set about trying to identify this molecule. At that stage he assumed, as did all biochemists, that the catalyst was an enzyme (a type of protein with a catalytic action).
Collaborating with Arthur Zaug, Cech reproduced the manufacture of rRNA from ribosomal deoxyribonucleic acid (rDNA) in the laboratory. Their study was only the second time that rRNA had been made in a laboratory. They altered the conditions of the experiment, trying to remove the component that was catalyzing the reaction. After many failed experiments, they came to suspect that the rRNA was itself the catalyst for the reaction. Cech and Zaug proved this theory by means of an experiment. Using the techniques of genetic engineering, they introduced the Tetrahymena rDNA gene into bacteria and showed that the production of rRNA produced the catalytic effect. The action of the RNA cuts up molecules and joins them up again—”splicing” them. Understanding this action is crucial to the genetic-engineering technique called gene-splicing.
Cech and Zaug’s discovery solved a problem concerning the origin of life: which came first, enzymes or DNA and RNA? It had seemed that if DNA and RNA had appeared first, there would have been no catalysts for the protein-building activities that they control. If proteins had appeared first, it was hard to see how DNA and RNA could have taken charge of the protein-building processes. After Cech and Zaug’s discovery, together with those of Sidney Altman, many scientists came to believe that, in the earliest stages of life on the earth, the most complex molecules were made of RNA, which both carried genetic information and catalyzed biochemical reactions.
Cech was born in Chicago, on Dec. 8, 1947. He studied biochemistry at the University of California at Berkeley. He then worked at Massachusetts Institute of Technology and subsequently at the University of Colorado. From 2000 to 2009, Cech served as president of the Howard Hughes Medical Institute, a medical research institute in Maryland, though he also maintained a research laboratory at the University of Colorado. In 2009, he returned to full-time research and teaching at Colorado.
