After completing his NSF Postdoctoral Fellow at the
University of Copenhagen, he relocated to New York City to take up a faculty appointment at
Columbia University. He served as an assistant professor from 1961 to 1963 and as an associate professor from 1963 to 1965.
Gray also trained future leaders of several major science research universities. Four of his doctoral students became presidents or chancellors of University of Rhode Island, Iowa State University, University of North Carolina at Chapel Hill, and Washington University in St. Louis.[8]
Over the past twenty-five years the Gray group has been measuring the kinetics of long-range ET reactions in metalloproteins labeled with inorganic
redox reagents. Early research by his lab members showed that details of the internal structures of the proteins dominate the ET rates.[10] Current research is aimed at understanding how intermediate protein radicals accelerate long-range ET. In collaboration with
Jay R. Winkler of the
Beckman Institute at Caltech they have developed new techniques for measuring ET rates in crystals of Ru-, Os-, and Re-modified
azurins, as well as crystals of Fe(III)-
cytochrome c doped with Zn(II)-cytochrome c.[11] This method of integrating
photosensitizers into protein crystals has provided a powerful new tool for studying biochemical reaction dynamics.[12] The Gray/Winkler group is also using ET chemistry to probe the dynamics of
protein folding in
cytochrome c.[13]
Wilker, Jonathan J.; Dmochowski, Ivan J.; Dawson, John H.; Winkler, Jay R.; Gray, Harry B. (January 15, 1999). "Substrates for Rapid Delivery of Electrons and Holes to Buried Active Sites in Proteins". Angewandte Chemie International Edition. 38 (1–2): 89–92.
doi:
10.1002/(SICI)1521-3773(19990115)38:1/2<89::AID-ANIE89>3.0.CO;2-R.
Telford, Jason R.; Wittung-Stafshede, Pernilla; Gray, Harry B.; Winkler, Jay R. (November 1998). "Protein Folding Triggered by Electron Transfer". Accounts of Chemical Research. 31 (11): 755–763.
doi:
10.1021/ar970078t.
Gray has made generative contributions to the understanding of chemical bonding of metal complexes, mechanisms of inorganic reactions, spectroscopy and magneto-chemistry of inorganic compounds. His study of the first trigonal prismatic complexes is one such example. Harry Gray's most significant work lies at the interface between
chemistry and
biology. As a pioneer of the important and thriving field of
bioinorganic chemistry, he has made many key contributions, the most important of which is the development of fundamental understanding of electron transfer in biological systems, at the atomic level.[28]
^Theopold, Klaus H. (September 2005). "The 2004 Benjamin Franklin Medal in Chemistry presented to Harry B. Gray". Journal of the Franklin Institute. 342 (6): 586–591.
doi:
10.1016/j.jfranklin.2005.04.015.