Correction

BIOCHEMISTRY. For the article “Structure and function from the circadian clock protein KaiA of Synechococcus elongatus: A potential clock input mechanism,” by Stanly B. Williams, Ioannis Vakonakis, Susan S. Golden, and Andy C. LiWang, which appeared in number 24, November 26, 2002, of Proc. Natl. Acad. Sci. USA (99, 15357–15362; First Published November 15, 2002; 10.1073/pnas.232517099), on page 15358, left column, third full paragraph, lines 9 and 15, the terms H^γ and H^Δ appeared incorrectly due to printer's errors. In line 9, H^γ should read H^β and, in line 15, H^Δ should read H^δ.