Robert William Holley ( January 28 , 1922 ; Urbana , Illinois â `` February 11 , 1993 ) was an American biochemist who shared the Nobel Prize in Physiology or Medicine , which he won for describing the structures for alanine transfer RNA , linking DNA and protein synthesis . Robert William Holley ( January 28 , 1922 -- February 11 , 1993 ) was an American biochemist , he shared the Nobel Prize in Physiology or Medicine in 1968 ( with Har Gobind Khorana and Marshall Warren Nirenberg ) for describing the structure of alanine transfer RNA , linking DNA and protein synthesis .