Recorded: 08 Jun 2006
The question about how amino acids were ordered was not a problem that the biochemists were interested at the time. This was a problem that the molecular biologists Watson and Crick and their associate Sydney Brenner and many others. The information question. How the information in DNA got the protein and in what form was not a question that we biochemists were interested in initially.
What we were interested in is simply being able to demonstrate that certain ingredients taken from a cell and these were animal cells, when put into the test tube with radioactive amino acids would catalyze or encourage if you will the synthesis of protein using those radioactive amino acids, Radioactivity simply being used as a means of demonstrating that the amino acids had been incorporated in the protein.
So we were primarily interested in the role of the ribosome the role of the now as we understood these activating enzymes the role of an energy source like ATP and the resulting incorporation into proteins on ribosomes.
So the Zamecnik group was largely responsible for working out those details steps in protein synthesis, but not contributing anything to a knowledge about how the order of amino acids was determined which was obviously the next most important question.
Mahlon Hoagland, a molecular biologist who was one of the discoverer of the transfer ribonucleic acid - tRNA. He received a medical degree from Harvard Medical School in 1948. He served as a doctor during the Second World War. When the War ended he returned to Harvard and became researcher in the Huntington Laboratories at the Massachusetts General Hospital in Boston. He worked in the bacteriology and immunology department of Harvard Medical School from 1952 till 1967.
Working together with Paul Zamecnik and Elizabeth Keller he discovered the initial steps of protein synthesis. Two years later in 1958 Hoagland and Zemecnik discovered tRNA. His main input to the laboratory was in his work with amino acid activating enzymes. He noticed that certain enzymes were required to activate amino acids so they could combine with tRNA molecules and eventually be incorporated into new protein molecules. These enzymes were named aminoacyl tRNA synthetases.
In 1957 Hoagland moved to Cambridge where he worked for a year with Crick at Cambridge University. Working together they tried to explain the genetic code.
He was Associate Professor of Microbiology at Harvard Medical School and in 1967 was appointed professor in the biochemistry department at the Dartmouth Medical School. After 3 years he left Dartmouth and became Director and President of the Worcester Foundation for Experimental Biology in Massachusetts. He retired in 1985.
Mahlon Hoagland was awarded the Franklin Medal for life science. He was a member of the American Academy of Arts and Sciences and the US National Academy of Sciences. He died on September 19, 2009.
More Information: Wikipedia