text: DksA is a 17-kDa protein, its structure is similar to GreA and GreB, which are well-characterized transcriptional elongation factors. GreA and GreB bind directly to RNAP rather than DNA and act by inserting their N-terminal coiled-coil finger domain through the RNAP secondary channel. Two conserved acidic residues at the tip of the finger domain are necessary to induce RNAP's intrinsic ability to cleave backtracked RNA. DksA also possesses two acidic residues at its finger tip, but it does not induce nucleolytic cleavage activity. Instead, these residues are proposed to stabilize ppGpp binding to RNAP by mutual coordination of an Mg2+ ion that is crucial for polymerization.