QURAN (Khorana), Xap Gobind( Indo-American biophysicist Nobel Prize in Physiology or Medicine, 1968)
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Biography QURAN (Khorana), Xap Gobind
genus. January 9, 1922
Indo-American biophysicist Har Gobind Quran was born in Raipur, a small village in Punjab province (now Pakistan). His parents were Indian citizens Ganpat Rai Koran, the tax collector in the British colonial administration, and Krishna Quran (Devi). Har Gobind was the youngest of five children. Despite the poverty, the family K. was one of the few literate families in Raipur. Primary K. received in extracurricular class, which dealt with rural teacher. Then he graduated from high school in Multan (Punjab), and then studied chemistry at Punjab University in Lahore. In 1943, Mr.. he received at this university bachelor of science degree with honors, and two years later - a master of science degree with honors.
In 1945, Mr.. K. received a government scholarship and went to study organic chemistry at the University of Liverpool. In 1948, Mr.. for thesis, . dedicated chemical pigments violatseinu, . staining some bacterial cells, . He received his doctorate in organic chemistry, . then within a year he studied the chemical structure of some alkaloids (organic bases), together with Vladimir Prelog of Zurich Federal Institute of Technology in Switzerland,
. At the end of 1949. K. was appointed Research Fellow at Cambridge University. Here, working with Alexander Todd, he became interested in biochemistry of nucleic acids - high-molecular organic compounds contained in the nuclei of cells.
In 1952, Mr.. K. became director department organicheskoi khimii Research Board British Columbia at University of British Columbia in Vancouver (Canada). Here he studied chemical structure atsetilkoenzima And. Enzymes, or enzymes - are biologically active substances of protein nature, accelerating the biochemical reactions in cells, and the coenzyme (coenzymes) - a compound is usually included in the composition of enzymes and ensure their active. A Atsetilkoenzim open Fritz Lippmann in 1945, is a condensation product of coenzyme A with acetic acid and plays a key role in carbohydrate, fat and protein in cells. In 1949, Mr.. K. and his colleague John Moffat synthesized atsetilkoenzim A. As they develop the method was much simpler and cheaper, . than preexisting ways allocating this substance from drozhzhei, . He gave the opportunity to receive atsetilkoenzim A in quantities, . necessary for studying such cellular processes, . as the breakdown of carbohydrates to release energy,
. This work brought to. worldwide recognition.
In 1960, Mr.. K. was appointed as one of the leaders of the Institute studies the enzymes the University of Wisconsin in Madison. The following year he published a paper 'The value of the latest achievements in the chemistry of esters of phosphoric acid for the biological processes' ( 'Some Recent Developments in the Chemistry of Phosphate Esters of Biological Interest'). In 1963, Mr.. He was appointed one of the editors 'Journal of the American Chemical Society' ( 'Journal of the American Chemical Society'). In the next year to. He was appointed professor of biological sciences at the University of Wisconsin. Since that time, he began studying the major problems of modern genetics - biochemistry of nucleic acids, biosynthesis of cellular proteins (enzymes) and the nature of genes.
. Genetics as a science was born in 1866, when Gregor Mendel published the work on the inheritance of color flower garden peas
. Mendel believed that the inheritance of physical characteristics of the organism meet certain 'elements', which are now called genes. In 1869, Mr.. Friedrich Miescher discovered that the genes are localized in the chromosomes of the cell nuclei. In the first half of XX century. as a result of numerous biochemical studies have elucidated the structure of two nucleic acids - ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Genes are formed by the DNA that controls the synthesis of cell proteins, enzymes and coenzymes and regulating biochemical processes in cells.
In 1953, Mr.. Francis Crick and James D. Watson deciphered the three-dimensional structure of DNA. DNA was similar to the rope ladder, rolled into a double helix. The double helix of DNA consists of two chains of nucleotides, each of which in turn formed carbohydrate deoxyribose, nitrogenous bases and phosphate. A nucleotide phosphate groups linked to each other, and inside the double helix, they are connected through a pair of nitrogenous bases ( 'stairs'). The alternation of the four bases determines the genetic code of DNA. The triplet of bases (ie. sequence of three bases) is a genetic instructions for the inclusion of an amino acid in the protein molecule, consisting of chains of amino acids. A gene contains a set of instructions for the synthesis of one protein molecule.
RNA molecules, also composed of nucleotide chains, duplicating the genetic code of DNA and transferred it to the cytoplasmic organelles - the ribosomes, where protein synthesis occurs. In addition, the RNA is responsible for amino acid transport to the site of synthesis.
In the early 60-ies. K. engaged in deciphering the genetic code. DNA encodes 20 amino acids, and the number of possible types of triplets formed by four nucleotides with different bases, is 4.4.4 = 64. K. decided to find out what sequence of bases in triplet encodes each of the 20 amino acids. Shortly before, a researcher at the National Institutes of Health, Marshall U. Nirenberg has developed a system for the synthesis of protein molecules consisting of a mixture of DNA, RNA, amino acids, ribosomes and the necessary enzymes.
Using a system of Nirenberg K. conducted a series of experiments, which could determine the sequence of nucleotides in the triplets encoding each of the 20 amino acids. He found that certain amino acids corresponds to more than one triplet, hence it was concluded that the genetic code from an evolutionary point of view of imperfect. K. and his colleagues synthesized strands of DNA and RNA, consisting of 64 possible triplets, and identified those that serve as a signal for the beginning and end of the biosynthesis of specific protein. In addition, they studied the chemical structure of the secondary transport of RNA - RNA species that transfers amino acids to the ribosomes. Primary structure - a sequence of nucleotides from one or another reason in the circuit, a secondary three-dimensional structure depends on in what parts of this chain is bent and in contact with itself. It turned out that in its secondary structure of RNA resembles Transportation trifoliate clover. The sequence of nucleotides in the 'middle leaflet' complementary to (ie. complements) the nucleotide sequence of messenger RNA, which overwrites the genetic code of DNA for transfer to the ribosomes. With this transfer of incorporation of amino acids in the protein chain is in the required sequence.
In 1968. K., Robert Y. Holley and Nirenberg was awarded the Nobel Prize in Physiology or Medicine 'for deciphering the genetic code and its role in protein synthesis'. In the congratulatory speech, a researcher at the Karolinska Institute, Peter Reichardt compared nucleic acids and proteins with the language, and their constituent elements - with the letters of the alphabet. He said: 'The chemical structure of nucleic acids determines the chemical structure of the protein and nucleic acid alphabet - the alphabet of proteins. The genetic code - is a dictionary, through which a transition from one alphabet to another '. Reichardt also added that the synthesis of nucleic acids, carried out by AK, is 'a necessary condition for a final solution to the problem of the genetic code'.
Two years after receiving the Nobel Prize to. and his colleagues first synthesized DNA containing 27 nucleotides corresponding to the yeast gene. They then synthesized the gene of Escherichia coli Escherichia coli. Since 1971. K. He was a professor of biology and chemistry at the Massachusetts Institute of Technology.
In 1952, Mr.. K. married a Swiss-born Esther Elizabeth Sibler. In the family they had a son and two daughters. In 1966, Mr.. K. received U.S. citizenship. K. very devoted to science, can work even without a holiday, so one day he did not take leave for 12 years in a row. K. likes to listen to music and go on walks, during which he wrote came to mind ideas.
To. been awarded many prizes, t.ch. Merck Prize of the Canadian Institute for Chemistry (1958), . Prize Louisa Gross Horwitz, Columbia University (1968), . Albert Lasker Award for basic medical research (1968) and Willard Gibbs medal of the American Chemical Society (1974),
. He is a member of the National Academy of Sciences of the USA, the American Association for the Advancement of Science, American Chemical Society and American Society of Biochemistry