Nirenberg (Nirenberg), Marshall W.

genus. April 10, 1927
Marshall Warren Nirenberg, American biochemist, born in New York, Harry and Minerva Nirenberg. When Marshall was 12 years old, the family moved to Orlando (Florida). In 1944, Mr.. N. was enrolled in the University of Florida, where he studied zoology and biology, which interested him since childhood. From 1945 to 1947, as a student last year, he worked as an assistant in the department of biology, where he was able to check their teaching abilities. He also studied biochemistry in the laboratory of food, acquiring experience in working with radioisotopes - radioactive elements, which can drive at the substance and then tracked their activity in chemical reactions.
After receiving in 1948. bachelor's degree from the University of Florida N. proceeded to completion of training in the department of biology. As a researcher he spent a year in the laboratory of food and wrote a dissertation on the taxonomy and ecology of the May flies (typical insect Florida) for the degree of Master. In 1952, Mr.. he was awarded a master's degree in biology. After the transition to the University of Michigan in Ann Arbor H. studied biochemistry as a teacher-trainee. In 1957. He received his doctorate in biochemistry, with a thesis dedicated recycling hexose (monosaccharide containing in its molecule 6 carbon atoms) cancer cells.
In the same year, H. Postdoctoral Fellowship was awarded to the American Cancer Society to study at the Institute of Arthritis and Metabolic Diseases National Institute of Health (NIH) in Bethesda (Maryland) led Devita Steta. And two years later he received a grant of the National Board of Health of the U.S., which enabled him to study the biochemistry of substances that control the biosynthesis of protein. In 1960, Mr.. N. became research associate in biochemistry in the department of metabolic enzymes of the Institute of Arthritis and Metabolic Diseases, where she first began work on deciphering the genetic code.
. Genetics as a science was born in 1866, following the publication of studies of Gregor Mendel on inheritance painting of flowers in the garden pea
. Mendel suggested that the 'elements', now called the genes carry the inheritance of physical characteristics of the organism. In 1869, Mr.. Swiss biochemist Friedrich Miescher discovered nucleic acids, but only in the first half of XX century. been clarified their biochemical properties. There are two types of nucleic acids: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Genes are composed of parts of the DNA molecule that directs the synthesis of cell proteins, enzymes and coenzymes. Enzymes are proteins that serve as a catalyst for biochemical reactions in the cell; nucleotides as necessary to ensure the activity of enzymes.
Francis Crick and James D. Watson determined the chemical structure of DNA, showed in 1953 that the molecule has the shape of the double helix like a spiral staircase. Each DNA chain is a chain of nucleotides, consisting of deoxyribose (monosaccharide), nitrogenous bases and phosphate molecules. Phosphate molecules bind nucleotides along the entire chain. Two strands of DNA are connected within the pairs of nitrogenous bases of type 'ladder rungs'. DNA contains four nitrogenous bases: adenine, thymine, guanine and cytosine. Molecule of adenine in the DNA chain is always paired with thymine molecule of another chain DNA molecule is similar to guanine always associated with a molecule of cytosine. Thus, the two complementary strands of DNA, and DNA replication can be represented as follows: two chains are separated from each other and parallel to each of them is synthesized new nucleotide chain. The sequence of nitrogenous bases in DNA is the genetic code, ie. triplet of nucleotides encodes the genetic instructions for incorporating a single amino acid in the protein molecule. (Proteins are formed from amino acids linked in a chain.) Gene contains the instructions on the biosynthesis of an entire protein molecule.
. RNA molecules, which are also formed by nucleotide chains, make a copy of the genetic code of DNA in the nucleus and carry it to the cytoplasm to the ribosomes, where protein molecules are formed
. RNA is also responsible for the transfer of amino acids to the site of protein synthesis, thus ensuring their connection in the proper sequence.
Shortly before the beginning of research H. on the biochemistry of nucleic acids in the NIH were isolated and purified enzymes responsible for the biosynthesis of DNA and RNA. In the early 60-ies. N. and his colleagues conducted an important series of experiments, which allowed them to decipher the genetic code. First, they synthesized poliuratsil, an RNA molecule, which contains only uracil (RNA, unlike DNA contains uracil instead of thymine). The researchers then placed poliuratsil in cell-free experimental system, formed by careful grinding of bacteria, which would produce a mixture of amino acids, RNA, ribosomes, the necessary enzymes and other substances. Poliuratsilovaya RNA directed the synthesis of protein molecules consisting of chains of molecules of amino acid phenylalanine. Consequently, the code for phenylalanine was a triplet of uracil-uracil-uracil (TK. uracil is the only nitrogenous bases in poliuratsile) or UUU. Because DNA contains 4 nitrogen bases, and the genetic code is formed from the triplet of nitrogen bases, there are 64 (4 x 4 x 4) possible triplet combinations for DNA. N. and his colleagues managed to synthesize all possible triplet sequences by repeating the cell-free experiments with each of them and opening the way codes of triplets of nitrogen bases for all 20 amino acids. Some of the amino acids encoded by more than one triplet, and some triplets are known as 'meaningless', tk. they do not encode any single amino acid. N. discovered that the 'mindless triplets', as a point in the proposal may signal the end of the process of biosynthesis of the cell. He and his colleagues conducted a later follow-up experiments to determine the sequence of nitrogenous bases in each triplet.
. The genetic code controls not only the formation of all the proteins the body needs to maintain its existence, but also the transmission of hereditary traits
. Deciphering the code, H. provided information that eventually may allow researchers to control and eliminate hereditary diseases caused by genetic defects.
In 1968. N. shared the Nobel Prize in Physiology or Medicine with Robert Y. Halls and Khar Gobind Koran, which was awarded to them 'for deciphering the genetic code and its function in protein synthesis'. In his Nobel lecture H. said: 'The transfer of information from nucleic acid to protein synthesis occurs sequentially, in accordance with a systematic code for the relatively simple rules. Each unit of the nucleic acid determines the type of selected molecules, their position relative to the previous selected molecule and the time of the event relative to the previous. Thus, the nucleic acid functions both as a matrix for other molecules and the biological clock '.
Once the genetic code was cracked, H. drew attention to the cellular mechanisms of control, hoping to understand why a particular set of biochemical reactions takes place in a given cell. He is also interested in how different types of cells such as nerve and muscle, differentiate during embryonic development or in case of danger to the environment. His work has given reason to believe that the genetic code of mammals, there are several billion years and that it is the same in all species.
Since 1966. N. - Chief biochemist in the genetic laboratory of the National Institute of Heart, Lung, and Blood. He and his wife, nee PEROLS Salzman, a biochemist whom he married in 1961, live in Bethesda (Maryland).
Numerous awards H. include the National Medal of Science National Research Society (1965), . Medal of the Franklin Institute Franklinovskogo dissemination of technical knowledge (1968), . Priestley Medal of the American Chemical Society (1968) and the award-Louise Gross Horwitz Columbia University (1968),
. He - a member of the National Academy of Sciences, the American Chemical Society, the Biophysical Society and the Society for Evolutionary Biology, has honorary degrees from universities in Michigan, Chicago, Windsor, Yale University. George Washington and the Weizmann Institute (Israel).