Figure 4.

Nucleic acid strand separation in our model of the CTP-bound POLRMT complex. A, the separation of downstream DNA strands by conserved residues in the fingers subdomain. The positions of the fingers and thumb subdomains are compared with their corresponding positions in the 4BOC starting structure, shown in dark brown. Line representation is used to show Tyr¹⁰⁰⁴ and Trp¹⁰²⁶, and the DNA template and nontemplate bases that interact with Tyr¹⁰⁰⁴ and Trp¹⁰²⁶, respectively; CTP is shown in ball-and-stick mode. B, the separation of the upstream DNA template from the RNA transcript by conserved residues belonging to the intercalating hairpin. The position of the intercalating hairpin is compared with its corresponding position in the 4BOC starting structure, shown in light green. Line representation is used to show Ile⁶¹⁸ and Ile⁶²⁰, and the RNA transcript and DNA template bases that interact with Ile⁶¹⁸ and Ile⁶²⁰, respectively; CTP is shown in ball-and-stick mode.