File:Doi.10.1128.JVI.00175-20.F9.large.jpg

English: Structural models of the Mononegavirales RNA synthesis. (A) The cartoon diagrams of recently reported structures of the Rhabdoviridae (VSV and RABV), Paramyxoviridae (HPIV), and Pneumoviridae (HRSV and HMPV) polymerases. The same color scheme as Fig. 2. (B) The modeled initiation and elongation complexes. The RdRp domain of the L proteins of Rhabdoviridae (VSV), Paramyxoviridae (HPIV), and Pneumoviridae (HRSV) with modeled RNA template from reovirus λ3 polymerase (PDB: 1N1H), FluB polymerase (PDB: 6QCV), and FluB polymerase (PDB: 6QCT), respectively. The same color scheme for the RdRp domain of Mononegavirales L. The priming loop (from the Cap domain) and the support helix (from the RdRp domain) are colored in orange. The modeled RNA template and RNA transcript are shown in yellow and pink, respectively. (C) The proposed cartoon models of the initiation and elongation stages on the nucleoprotein (N) encapsidated N:RNA (NC) template. Initiation, the priming loop and support helix are at the close approximate of the GDN active site of the RdRp domain of L; elongation (early stage), the priming loop is away from but the support helix stays at the close approximate to the active site of the RdRp domain of L; elongation (late stage), the priming loop is away from the active site of the RdRp domain of L, the support helix is missing, and the CD, MT, and CTD domains of L are disordered and linked by dashed lines. The nucleoprotein (N) protein is shown as the yellow oval. The RNA template, RNA transcript, and the flexible linker are shown in the black, blue, and red lines, respectively. The priming loop and support helix are shown as the thick orange bar and cylinder, respectively. The PDB accession codes are underlined.