Harry B. Gray

Assistant: Aracely Sustaita

Gray developed the ligand field theory of metal-oxo multiple bonding during a 1960-61 postdoctoral stint in Copenhagen. After taking up a faculty post Columbia, work on the electronic structures of tetra-oxo complexes led to discovery of an "oxo wall" between iron-ruthenium-osmium and cobalt-rhodium-iridium in the periodic table.

In the early 1960s, Gray found that coordinated ligands could be redox active, launching widespread study of "non-innocent ligands", a field that has grown exponentially for years. Today, metal complexes containing non-innocent ligands are widely used as sensors, electronic conductors, and catalysts.

Upon arrival at Caltech in 1966, Gray turned his attention to the role of metals in living systems. His 1982 JACS paper describes the first measurement of electron tunneling in a protein of known structure, a discovery that sparked a line of inquiry that has flourished for decades. Research on long-range electron transfer has led to profound changes in our understanding of biological electron flow and energy transduction. Notably, Gray discovered that biological electron transport over exceptionally long distances requires multiple hole-tunneling steps, called "hole hopping". In 2015, he and Jay Winkler proposed that moving holes through redox-active amino acid residues could protect living cells from catastrophic oxidative damage. Interrogation of the enormous protein structure database revealed that many proteins contain redox-active tyrosine and tryptophan chains. Such chains could protect proteins from damage by transferring oxidizing holes to surface sites where they can be disarmed by cellular reductants.

Currently, Gray is collaborating with Caltech colleagues in experimental and computational investigations of metal-ion binding to the intrinsically disordered C-terminal peptide region of SARS-Cov-2 nonstructural protein-1 (Nsp1). Nsp1, a drug target, is believed to inhibit host protein synthesis by blocking mRNA access to the 40S ribosome entrance tunnel. The group is testing a hypothesis that coordination to transition metal ions will prevent virulent biomolecules from attacking host cells.

Gray has published over 950 research papers and given named lectures on six continents and in all 50 US States. His many awards and honors include the National Medal of Science (1986); the Linderstrøm-Lang Prize (1992); the Gibbs Medal (1992); the Harvey Prize (2000); the NAS Award in Chemical Sciences (2003); the Benjamin Franklin Medal (2004); the Wolf Prize (2004); the Welch Award (2009); the Richards Medal (2014); the Cotton Medal (2018); the Westheimer Prize (2018); the Feynman Prize (2018); seven national awards from the American Chemical Society, including the Priestley Medal (1991); and 22 honorary doctorates. He is a member of the National Academy of Sciences; the American Academy of Arts and Sciences; the American Philosophical Society; a foreign member of the Royal Danish Academy of Sciences and Letters; the Royal Swedish Academy of Sciences; the Royal Society of Great Britain; and the Accademia Nazionale dei Lincei. He has mentored several hundred students and postdocs during his career, including over 100 women, and six have been presidents of seven universities.