TY - JOUR TI - A putative ATPase mediates RNA transcription and capping in a dsRNA virus AU - Yu, Xuekui AU - Jiang, Jiansen AU - Sun, Jingchen AU - Zhou, Z Hong A2 - Scheres, Sjors HW VL - 4 PY - 2015 DA - 2015/08/04 SP - e07901 C1 - eLife 2015;4:e07901 DO - 10.7554/eLife.07901 UR - https://doi.org/10.7554/eLife.07901 AB - mRNA transcription in dsRNA viruses is a highly regulated process but the mechanism of this regulation is not known. Here, by nucleoside triphosphatase (NTPase) assay and comparisons of six high-resolution (2.9–3.1 Å) cryo-electron microscopy structures of cytoplasmic polyhedrosis virus with bound ligands, we show that the large sub-domain of the guanylyltransferase (GTase) domain of the turret protein (TP) also has an ATP-binding site and is likely an ATPase. S-adenosyl-L-methionine (SAM) acts as a signal and binds the methylase-2 domain of TP to induce conformational change of the viral capsid, which in turn activates the putative ATPase. ATP binding/hydrolysis leads to an enlarged capsid for efficient mRNA synthesis, an open GTase domain for His217-mediated guanylyl transfer, and an open methylase-1 domain for SAM binding and methyl transfer. Taken together, our data support a role of the putative ATPase in mediating the activation of mRNA transcription and capping within the confines of the virus. KW - viral ATPase KW - histidine-mediated guanylyl transfer KW - allosteric regulation KW - conformational change JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -