Har Gobind Khorana

Har Gobind Khorana (born January 9, 1922) is an American molecular biologist born of Punjabi heritage in British India. He was awarded the Nobel prize (shared with Robert W. Holley and Marshall Warren Nirenberg) in 1968 for his work on the interpretation of the genetic code and its function in protein synthesis. Khorana and Nirenberg were also awarded the Louisa Gross Horwitz Prize from Columbia University in the same year. He became a naturalized citizen of the United States in 1966. He currently lives in Cambridge, Massachusetts, United States serving on the MIT Chemistry faculty.

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Early life and Education

Khorana was born in Raipur, Kabir Wala, Multan, a poor village in Pakistan. His father was the village "patwari", or taxation official. He was homeschooled by his father, and he later attended D.A.V. Multan High School. He finished his B.Sc. from Punjab University, Lahore in 1943 and M.Sc from Punjab University in 1945. In 1945, he began studies at the University of Liverpool. After earning a PhD in 1948, he continued his postdoctoral studies in Zürich (1948-49). Subsequently, he spent two years at Cambridge and his interests in proteins and nucleic acids took root at that time. In 1952 he went to the University of British Columbia, Vancouver and in 1960 moved to the University of Wisconsin-Madison. In 1970 Dr. Khorana became the Alfred Sloan Professor of Biology and Chemistry at the Massachusetts Institute of Technology where he continues to work.

Family

Khorana was married in 1952 to Esther Elizabeth Sibler, who is of Swiss origin. They have three children: Julia Elizabeth (born May 4th, 1953), Emily Anne (born October 18th, 1954), and Dave Roy (born July 26th, 1958).

Khorana’s work & Nobel Prize

Ribonucleic acid (RNA) with two repeating units (UCUCUCU → UCU CUC UCU) produced two alternating amino acids. This, combined with the Nirenberg and Leder experiment, showed that UCU codes for Serine and CUC codes for Leucine.

RNAs with three repeating units (UACUACUA → UAC UAC UAC, or ACU ACU ACU, or CUA CUA CUA) produced three different strings of amino acids.

RNAs with four repeating units including UAG, UAA, or UGA, produced only dipeptides and tripeptides thus revealing that UAG, UAA and UGA are stop codons.

With this, Dr. Khorana and his team had established that the mother of all codes, the biological language common to all living organisms, is spelled out in three-letter words: each set of three nucleotides codes for a specific amino acid. Their Nobel lecture was delivered on December 12, 1968. Dr. Khorana was also the first to synthesize oligonucleotides, that is, strings of nucleotides. He was the first to isolate DNA ligase, an enzyme that links pieces of DNA together. These custom-designed pieces of artificial genes are widely used in biology labs for sequencing, cloning and engineering new plants and animals. This invention of Dr. Khorana has become automated and commercialized so that anyone now can order a synthetic gene from any of a number of companies-- one merely needs to fax the genetic sequence to one of the companies to receive an oligonucliotide with the desired sequence.

Awards

• Lasker Award, 1967
• Louisa Gross Horwitz Prize 1968
• Nobel Prize for Medicine 1968
• National Medal of Science 1987

Trivia

• Dr. Khorana is very famous in his native Punjab and a short story about his early career is taught widely at the high school level. It details his efforts to find a teaching or research job in Punjab after getting his Ph.D. and how he was unable to find a job despite his excellent credentials since he did not have political "pull" needed for such jobs. The story ends in a sentence that is now legendary in Punjab : "Mr. Khorana, the job was yours and we were about to sign the offer letter but then the Minister called and recommended his nephew and....". Dr. Khorana returned to Liverpool shortly thereafter and never returned to work in Punjab.

References

• The Official Site of Louisa Gross Horwitz Prize