New Delhi: January 9 marks the birth anniversary of Nobel laureate Har Gobind Khorana. Khorana was awarded the 1968 Nobel Prize in Physiology or Medicine along with Robert W. Holley and Marshall W. Nirenberg "for their interpretation of the genetic code and its function in protein synthesis," the Nobel Prize Organisation said on its website. Their research helped show how the nucleotides in nucleic acids, which carry the genetic code of the cell, control the cell's synthesis of proteins.

The Feat That Won Khorana The Nobel Prize


Khorana won the prestigious Nobel Prize for his work on the human genetic code. Though it was established in the 1950s that genetic information is transferred from DNA to RNA to protein and that one sequence of three nucleotides in DNA corresponds to a certain amino acid within a protein, it was not how this genetic code could be cracked.

Marshall Nirenberg had discovered the first piece of the puzzle, and in the years that followed, the remainder of the code was generally revealed. Khorana made important contributions to the field by building different RNA chains with the help of enzymes. He was able to produce proteins using these enzymes. The rest of the puzzle could be solved with the help of the amino acid sequences of these proteins.

Khorana, in the 1960s, confirmed Nirenberg's findings that the way the four different types of nucleotides are arranged on the spiral "staircase" of the DNA molecule determines the chemical composition and function of a new cell, according to Britannica.

In order to produce the desired amino acid, a particular combination of nucleotides is read off along a strand of DNA. There are 64 possible combinations of nucleotides that serve as instructions for the production of amino acids, or the building blocks of proteins.

Details about which serial combinations of nucleotides from which specific amino acids were added by Khorana. 

An important breakthrough was that Khorana proved that the nucleotide code is always transmitted to the cell in groups of three, called codons. He also determined that some of the codons prompt the cell to start or stop the manufacture of proteins.

Khorana's Educational Background & Other Research Works


Born in a little village in Punjab, which is now part of eastern Pakistan, Khorana was the youngest of a family of one daughter and four sons. Khorana's family, though poor, was practically the only literate family in the village inhabited by around 100 people.

While he attended DAV High School in Multan, now West Punjab, he was greatly influenced by Ratan Lal, one of his teachers. 

Later, at Punjab University, Khorana obtained an MSc degree, under the supervision of Mahan Singh, an accurate experimentalist.

In 1945, the award of a Government of India Fellowship made it possible for Khorana to go to England where he studied for a Ph.D. degree at the University of Liverpool. There, Roger J S Beer was his supervisor. 

From 1948 to 1949, Khorana spent a postdoctoral year at the Eidgenõssische Technische in Zurich with Professor Vladmir Prelog. Khorana's thought and philosophy towards science, work, and effort were significantly moulded due to his association with Professor Prelog.

In the fall of 1949, Khorana spent a brief period in India and returned to England. He started working with Dr GW Kenner and Professor Alexander Todd, who is now Lord Todd. From 1950 to 1952, Khorana stayed in Cambridge, which is when interest in both proteins and nucleic acids took root in him. Under Sir Alexander Todd, Khorana began research on nucleic acids during his fellowship at the University of Cambridge in 1951.

Khorana got a job offer in 1952 from Dr Gordon M Shrum of British Columbia and went to Vancouver.

During the following years, a group, which Khorana was a part of, started to work in the field of biologically interesting phosphate esters and nucleic acids, with Dr Shrum's inspiration and encouragement and frequent help and scientific counsel from Dr Jack Campbell, who is now Head of the Department of Microbiology at the University of British Columbia. 

Khorana moved to the Institute for Enzyme Research at the University of Wisconsin in 1960 and became a naturalised citizen of the United States. 

Khorana had fellowships and professorships in Switzerland at the Swiss Federal Institute of Technology, in Canada, at the University of British Columbia, from 1952 to 1959, and at the University of Wisconsin from 1960 to 1970.

In 1970, Khorana made another contribution to genetics when he and his research team were able to synthesise the first artificial copy of a yeast gene. 

In subsequent research, he explored the molecular mechanisms underlying the cell signalling pathways of vision in vertebrates. He focussed mainly on the structure and function of rhodopsin, a light-sensitive protein found in the retina of the vertebrate eye, and also investigated mutations in rhodopsin that are associated with retinitis pigmentosa, which causes night blindness. 

He served as Professor of Biology at the Massachusetts Institute of Technology, from the fall of 1970 till his retirement in 2007.

He was also awarded the Albert Lasker Basic Medical Research Award in 1968, and the National Medal of Science in 1987.

Khorana, MIT's Alfred P. Sloan Professor of Biology and Chemistry emeritus, died of natural causes in Concord, Massachusetts, on November 9, 2011.