Christopher T. Walsh, 79, died Jan. 10 in Boston. He was known for his research on the biosynthesis of natural products, including antibiotics; for leadership roles at the Massachusetts Institute of Technology and Harvard Medical School; and for foundational contributions to the field of chemical biology.
Walsh’s lifelong interest in natural products began when he was an undergraduate at Harvard University. Working with chemist John Law and zoologist Edward O. Wilson, he identified the molecule responsible for fire ants’ pheromone trail (Nature 1965, DOI: 10.1038/207320b0).
Walsh joined the faculty at MIT in 1972 and studied reaction mechanisms in a diverse group of cofactor-dependent enzymes. Robert Pascal, a chemist at Tulane University who earned his PhD in Walsh’s lab, recalls in an email that almost every student worked on an independent enzyme, giving trainees great autonomy in their research.
Walsh was already chair of MIT’s Chemistry Department by the time he moved to Harvard Medical School in 1987 to lead the newly formed Department of Biological Chemistry and Molecular Pharmacology. While chair, he also spent 3 years as president of the Dana-Farber Cancer Institute before returning to the lab full-time in 1995.
Walsh and colleagues identified the enzymatic mechanism for microbial resistance to the antibiotic vancomycin, which inhibits bacterial cell wall–biosynthesis and was a drug of last resort at the time (Biochemistry 1991, DOI: 10.1021/bi00222a002). His lab continued to study natural products, making influential observations about biosynthetic gene clusters and determining the synthesis pathways of secondary metabolites, including polyketides and nonribosomal peptides.
Gerry Wright, a biochemist at McMaster University who was a postdoctoral scholar in Walsh’s lab at Harvard, remembers him as a clear, rigorous thinker whose search for the chemical logic underlying biological phenomena helped clarify many complex systems and launch the field of chemical biology.
Walsh was highly involved in the biopharmaceutical industry, serving as a consultant at Genzyme, Merck & Co., and Roche and as a director or scientific adviser for numerous successful start-ups. He authored three influential textbooks and supervised more than 250 graduate and postdoctoral trainees over the years. Those who spoke with C&EN recall his generosity with his time despite many obligations, along with his ability to be, in Wright’s words, “unflinchingly supportive—but not in a way that was syrupy.” He was a member of the National Academy of Sciences and the National Academy of Medicine and received the Welch Award in Chemistry and the Benjamin Franklin Medal in Chemistry, among other awards.