Following his graduate studies Holley remained associated with Cornell. He became an assistant professor of organic chemistry in 1948, and was appointed as professor of biochemistry in 1962. He began his research onRNA after spending a year's sabbatical (1955–1956) studying withJames F. Bonner at theCalifornia Institute of Technology.
Holley's research onRNA focused first on isolatingtransfer RNA (tRNA), and later on determining the sequence and structure of alaninetRNA, the molecule that incorporates theamino acidalanine intoproteins. Holley's team of researchers determined the tRNA's structure by using tworibonucleases to split the tRNA molecule into pieces. Each enzyme split the molecule at location points for specific nucleotides. By a process of "puzzling out" the structure of the pieces split by the two different enzymes, then comparing the pieces from both enzyme splits, the team eventually determined the entire structure of the molecule. The group of researchers includeElizabeth Beach Keller, who developed the cloverleaf model that describes transfer RNA, during the course of the research.[4]
The structure was completed in 1964,[5][6] and was a key discovery in explaining thesynthesis of proteins frommessenger RNA. It was also the first nucleotide sequence of aribonucleic acid ever determined. Holley was awarded the Nobel Prize in Physiology or Medicine in 1968 for this discovery,[7] andHar Gobind Khorana andMarshall W. Nirenberg were also awarded the prize that year for contributions to the understanding of protein synthesis.
Using the Holley team's method, other scientists determined the structures of the remaining tRNA's. A few years later the method was modified to help track the sequence of nucleotides in various bacterial, plant, and humanviruses. He died in 1993
