NIH · Public domain

Sidney Altman overturned the assumption that only proteins could catalyze chemical reactions inside a cell. Studying an enzyme complex called RNase P, he and his lab showed that its RNA component alone could carry out the catalysis, work that shared the 1989 Nobel Prize in Chemistry with Thomas Cech. He spent most of his career at Yale, where he was also dean of Yale College from 1985 to 1989.