Fig. 7: Model of initiation and elongation for L-P complex in RNA synthesis.
From: Structure of the Newcastle Disease Virus L protein in complex with tetrameric phosphoprotein
a In pre-initiation (represented by VSV), the priming loop is oriented in active site while the intrusion loop is towards the PRNTase ___domain. The product exit channel is blocked by PRNTase ___domain. The CD-MTase-CTD module is near the product exit channel. b In elongation-1 stage (represented by hMPV missing CD-MTase-CTD module), the priming loop is retracted from the active site and the intrusion loop is also located in the PRNTase ___domain. The PRNTase ___domain moves to expose RNA product exit channel. c In elongation-2 stage (represented by NDV), The priming loop is retracted from the active site and the intrusion loop extends into the active site. The CD-MTase-CTD module tilts upward, and the product channel is continuous through PRNTase and MTase. d In elongation-3 stage (represented by PIV5), the priming loop is retracted further from the active site; the intrusion loop raises upward from the active site. The MTase-CTD modules was rotated by ~70 degree, orienting MTase and CTD away from the product channel.
