Har Gobind Khorana

Har Gobind Khorana was a pioneering biochemist whose groundbreaking work fundamentally advanced the field of molecular biology. He shared the Nobel Prize in Physiology or Medicine in 1968 with Robert W. Holley and Marshall W. Nirenberg for interpreting the genetic code and elucidating its function in protein synthesis. His development of methods to chemically synthesize oligonucleotides provided the essential tools for modern genetic engineering and biotechnology.

Early life and education

Har Gobind Khorana was born in the small village of Raipur in the Punjab region of the British Raj. His father was a village patwari, or taxation clerk, and the family was among the few literate households in their community. Despite financial hardship, he excelled academically, earning a scholarship to attend the University of the Punjab in Lahore, where he received a Bachelor of Science and later a Master of Science degree. Awarded a Government of India Fellowship, he pursued doctoral studies at the University of Liverpool in England, earning a PhD in 1948 under the supervision of Roger J.S. Beer. He then conducted postdoctoral research with Vladimir Prelog at the Swiss Federal Institute of Technology in Zürich, which deeply influenced his approach to organic chemistry.

Research and scientific contributions

Khorana's early independent work at the University of British Columbia and later at the University of Wisconsin–Madison focused on nucleic acids and coenzyme A. His most critical breakthrough was the development of novel chemical methods to synthesize defined sequences of oligonucleotides, the short chains of nucleotides that form DNA and RNA. These synthetic tools enabled him and his team to design and build specific codons, the three-letter genetic words. By meticulously testing these synthetic messenger RNA molecules in a cell-free system, they deciphered the entire genetic code, confirming its triplet nature and demonstrating its universality across life. This work also revealed the specific nucleotide sequences that act as start codon and stop codon signals for protein synthesis.

Nobel Prize in Physiology or Medicine

In 1968, Har Gobind Khorana was awarded the Nobel Prize in Physiology or Medicine jointly with Marshall W. Nirenberg and Robert W. Holley. The Royal Swedish Academy of Sciences recognized their collective interpretation of the genetic code and its role in protein biosynthesis. While Nirenberg discovered the first word of the code, Khorana's chemical synthesis of entire genes provided the definitive proof and expanded the dictionary. Holley's work on determining the structure of transfer RNA complemented these findings. The prize highlighted a transformative period in molecular biology, moving from understanding the structure of DNA, as revealed by James Watson and Francis Crick, to fully cracking its informational cipher.

Later career and legacy

In 1970, Khorana moved to the Massachusetts Institute of Technology as the Alfred P. Sloan Professor of Biology and Chemistry, where he continued his pioneering research. His laboratory achieved the first total synthesis of a functional gene, specifically a tRNA gene from yeast, a monumental feat in synthetic biology. This work paved the way for modern recombinant DNA technology and the Human Genome Project. He also made significant contributions to understanding the structure and function of bacteriorhodopsin, a membrane protein critical in bioenergetics. He mentored numerous scientists who became leaders in academia and industry, and his foundational techniques remain cornerstones of genetic engineering, PCR, and DNA sequencing.

Awards and honors

Beyond the Nobel Prize, Har Gobind Khorana received numerous prestigious accolades throughout his career. He was elected a member of the United States National Academy of Sciences and a Fellow of the Royal Society. His awards include the Louisa Gross Horwitz Prize from Columbia University, the Albert Lasker Award for Basic Medical Research, the Gairdner Foundation International Award, and the National Medal of Science, presented by President Ronald Reagan. He held honorary doctorates from universities worldwide, including the University of Chicago and University of Liverpool. In 2007, the Government of India issued a postage stamp in his honor, and the Department of Biotechnology in India instituted the Har Gobind Khorana Innovative Young Biotechnologist Award to support young scientists.

Category:American biochemists Category:Nobel laureates in Physiology or Medicine Category:Recipients of the National Medal of Science