Biochemistry. In the article “Negative control of bacterial DNA replication by a cell cycle regulatory protein that binds at the chromosome origin” by Kim C. Quon, Bing Yang, Ibrahim J. Domian, Lucy Shapiro, and Gregory T. Marczynski, which appeared in number 1, January 6, 1998, of Proc. Natl. Acad. Sci. USA (95, 120–125), the authors wish to note that the institutional affiliations in the author line were incorrectly attributed. The correct affiliations are as follows. Bing Yang and Gregory T. Marczynski are at McGill University in Montreal, and Kim C. Quon is now at the Netherlands Cancer Institute.