For the article ‘ ‘ Interaction of RNA polymerase with forked DNA : Evidence for two kinetically significant intermediates on the pathway to the final complex

BIOCHEMISTRY. For the article ‘‘Interaction of RNA polymerase with forked DNA: Evidence for two kinetically significant intermediates on the pathway to the final complex,’’ by Laura Tsujikawa, Oleg V. Tsodikov, and Pieter L. deHaseth, which appeared in number 6, March 19, 2002, of Proc. Natl. Acad. Sci. USA (99, 3493–3498; First Published March 12, 2002; 10.1073 pnas.062487299), the authors note the following concerning RNA polymerase (RNAP) concentrations. No correction was made for the fraction of RNAP (0.5) that is active in promoter binding. With this correction, the values of K1 and Kapp (but not Kf) would increase by about a factor of 2. The relative values would remain essentially unchanged. Also, the legends to Figs. 2, 3, and 5 contain errors pertaining to the symbols used for data obtained with and without heparin challenge, the duration of the challenge, and the concentration of added heparin. The figures and the corrected legends appear below.