RNA-dependent RNA polymerase (RdRp), also known as Protein P2, is an essential enzyme involved in the replication and transcription of RNA in various organisms, including bacteriophages. RdRp catalyzes the synthesis of RNA from an RNA template, playing a central role in viral RNA metabolism [1]. It is responsible for the synthesis of both minus and plus-strand transcripts [2]. The RdRp P2 protein contains the RNA polymerase active site and is required for the replicase and transcriptase activities [3]. Additionally, it has been demonstrated to catalyze single-stranded RNA replication in vitro [1]. The P2 protein has been identified inside the unexpanded procapsid shell, indicating its involvement in minus RNA strand synthesis [4]. Furthermore, the P2 protein is part of the RNA polymerase complex and is involved in the regulation of viral RNA metabolism [1]. The P2 protein also utilizes its acidic C-terminal tail to regulate the RNA-directed RNA polymerase P2, highlighting its multifaceted role in RNA synthesis [3].
References:
[1] E. Makeyev and D. Bamford, "The polymerase subunit of a dsrna virus plays a central role in the regulation of viral rna metabolism", The Embo Journal, vol. 19, no. 22, p. 6275-6284, 2000. https://doi.org/10.1093/emboj/19.22.6275
[2] D. Nemecek, J. Heymann, J. Qiao, L. Mindich, & A. Steven, "Cryo-electron tomography of bacteriophage φ6 procapsids shows random occupancy of the binding sites for rna polymerase and packaging ntpase", Journal of Structural Biology, vol. 171, no. 3, p. 389-396, 2010. https://doi.org/10.1016/j.jsb.2010.06.005
[3] S. Alphonse, J. Arnold, S. Bhattacharya, H. Wang, B. Kloss, C. Cameronet al., "Cystoviral polymerase complex protein p7 uses its acidic c-terminal tail to regulate the rna-directed rna polymerase p2", Journal of Molecular Biology, vol. 426, no. 14, p. 2580-2593, 2014. https://doi.org/10.1016/j.jmb.2014.04.028
[4] J. Heymann, D. Nemecek, N. Cheng, J. Qiao, L. Mindich, & A. Steven, "Expansion of the bacteriophage φ6 procapsid revealed by electron cryo-microscopy", Microscopy and Microanalysis, vol. 15, no. S2, p. 586-587, 2009. https://doi.org/10.1017/s1431927609098390
