He shared the 1968 Nobel Prize for Physiology or Medicine with Marshall W. Nirenberg and Robert W. Holley for research that showed how the order of nucleotides in nucleic acids, which carry the genetic code of the cell, control the cell’s synthesis of proteins. Khorana and Nirenberg were also awarded the Louisa Gross Horwitz Prize from Columbia University in the same year.
Khorana was born in Raipur, British India (today Kabirwala in Pakistan). He was the youngest of five children of Ganpat Rai Khorana, a taxation clerk, and Krishna Devi Khorana. He served on the faculty of the University of British Columbia from 1952-1960, where he initiated his Nobel Prize winning work. He became a naturalized citizen of the United States in 1966, and subsequently received the National Medal of Science. He co-directed the Institute for Enzyme Research, became a professor of biochemistry in 1962 and was named Conrad A. Elvehjem Professor of Life Sciences at University of Wisconsin–Madison.He served as MIT's Alfred P. Sloan Professor of Biology and Chemistry, Emeritus and was a member of the Board of Scientific Governors at The Scripps Research Institute.
Ribonucleic acid (RNA) with three 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, 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 12 December 1968. Khorana was the first scientist to chemically synthesize oligonucleotides.
He extended the above to long DNA polymers using non-aqueous chemistry and assembled these into the first synthetic gene, using polymerase and ligase enzymes that link pieces of DNA together, as well as methods that anticipated the invention of polymerase chain reaction (PCR).These custom-designed pieces of artificial genes are widely used in biology labs for sequencing, cloning and engineering new plants and animals, and are integral to the expanding use of DNA analysis to understand gene-based human disease as well as human evolution. Khorana's invention(s) have become automated and commercialized so that anyone now can order a synthetic oligonucleotide or a gene from any of a number of companies. One merely needs to send the genetic sequence to one of the companies to receive an oligonucleotide with the desired sequence.
Since the middle of the 1970s, his lab has studied the biochemistry of bacteriorhodopsin, a membrane protein that converts light energy into chemical energy by creating a proton gradient.Later, his lab went on to study the structurally related visual pigment known as rhodopsin.
Har Gobind Khorana was born to parents Shrimati Krishna Devi Khorana, and Shri Ganpat Rai Khorana in Raipur, a little village in Punjab, which is now part of Pakistan. The correct date of his birth is not known; that shown in documents is January 9th, 1922. He was the youngest of a family of one daughter and four sons. His father was a «patwari», a village agricultural taxation clerk in the British Indian government. His father was dedicated to educating his children, and they were practically the only literate family in the village inhabited by about 100 people. Har Gobind Khorana attended D.A.V. High School in Multan, West Punjab; Ratan Lal, one of his teachers, influenced him greatly during that period. Later, he studied at the Punjab University in Lahore where he obtained an M. Sc. degree. Mahan Singh, a great teacher and accurate experimentalist, was his supervisor.
Khorana lived in British India until 1945, when the award of a Government of India Fellowship made it possible for him to go to England where he studied for a Ph. D. degree at the University of Liverpool. Roger J. S. Beer supervised his research and, in addition, looked after him diligently. This was the introduction of Khorana to Western civilization and culture. Khorana spent a postdoctoral year (1948-1949) at the Eidgenössische Technische Hochschule in Zurich with Professor Vladimir Prelog. The association with Professor Prelog molded immeasurably his thought and philosophy towards science, work, and effort.
After a brief period in independent India, in the fall of 1949, Khorana returned to England where he obtained a fellowship to work with Dr. (now Professor) G. W. Kenner and Professor (now Lord) A. R. Todd. He stayed in Cambridge from 1950 untill 1952. Again, this stay proved to be of decisive value to Khorana. Interest in both proteins and nucleic acids took root at that time.
A job offer in 1952 from Dr. Gordon M. Shrum of British Columbia (now Chancellor of Simon Fraser University, British Columbia) took him to Vancouver. The British Columbia Research Council offered at that time very little by way of facilities, but there was «the freedom», to use Dr. Shrum's words, to do what the researcher liked to do. During the following years, with Dr. Shrum's inspiration and encouragement and frequent help and scientific counsel from Dr. Jack Campbell (now Head of the Department of Microbiology at the University of British Columbia), a group began to work in the field of biologically interesting phosphate esters and nucleic acids. Among the many devoted and loyal colleagues of this period, there should, in particular, be mention of Dr. Gordon M. Tener (now a Professor in the Biochemistry Department of the University of British Columbia), who contributed much to the spiritual and intellectual well-being of the group.
In 1960 Khorana moved to the Institute for Enzyme Research at the University of Wisconsin. He became a naturalized citizen of the United States. As of the fall of 1970 Khorana has been Alfred P. Sloan Professor of Biology and Chemistry at the Massachusetts Institute of Technology.
Har Gobind Khorana was married in 1952 to Esther Elizabeth Sibler, who is of Swiss origin. Esther brought a consistent sense of purpose into his life at a time when, after six years' absence from the country of his birth, Khorana felt out of place everywhere and at home nowhere. They have three children: Julia Elizabeth (born May 4th, 1953), Emily Anne (born October 18th, 1954), and Dave Roy (born July 26th, 1958).
Khorana was elected as Foreign Member of the Royal Society (ForMemRS) in 1978. The University of Wisconsin-Madison, the Government of India (DBT Department of Biotechnology), and the Indo-US Science and Technology Forum jointly created the Khorana Program in 2007. The mission of the Khorana Program is to build a seamless community of scientists, industrialists, and social entrepreneurs in the United States and India.
The program is focused on three objectives: Providing graduate and undergraduate students with a transformative research experience, engaging partners in rural development and food, security, and facilitating public-private partnerships between the U.S. and India. In 2009, Khorana was hosted by the Khorana Program and honored at the 33rd Steenbock Symposium in Madison, Wisconsin.