Fig 1. Reaction schemes of transcript elongation.

A) Reaction scheme for the four states of the nucleotide addition cycle. B) Reaction scheme for the elongation states, determined by the transcript and the compounded rate constants that connect them: the κ-parameters signify forward movement by phosphodiester bond formation and the ς-parameters backtracking and dinucleotide cleavage of the nascent transcript. Note that the compounded rate constants in Fig. 1B are defined by the detailed rate constants in Fig. 1A, as described (see Methods for details).