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Published on: August 9, 2011
Structures of the mumps virus polymerase complex via cryo-electron microscopy
Tianhao Li1,2,3,4, Mingdong Liu1,2,3, Zhanxi Gu5,6
1School of Life Sciences, Department of Chemical Biology, Southern University of Science and Technology, Shenzhen, 518055, China.
Abstract:
The viral polymerase complex, comprising the large protein (L) and phosphoprotein (P), is crucial for both genome replication and transcription in non-segmented negative-strand RNA viruses (nsNSVs), while structures corresponding to these activities remain obscure. Here, we resolved two L-P complex conformations from the mumps virus (MuV), a typical member of nsNSVs, via cryogenic-electron microscopy. One conformation presents all five domains of L forming a continuous RNA tunnel to the methyltransferase domain (MTase), preferably as a transcription state. The other conformation has the appendage averaged out, which is inaccessible to MTase. In both conformations, parallel P tetramers are revealed around MuV L, which, together with structures of other nsNSVs, demonstrates the diverse origins of the L-binding X domain of P. Our study links varying structures of nsNSV polymerase complexes with genome replication and transcription and points to a sliding model for polymerase complexes to advance along the RNA templates.
Insights
Structural insights into the mumps virus polymerase complex reveal distinct conformations crucial for RNA replication and transcription. This study elucidates the viral polymerase
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- The viral polymerase complex (L-P) is essential for non-segmented negative-strand RNA virus (nsNSV) RNA replication and transcription.
- The precise structures of L-P complexes and their functional implications remain largely unknown.
Purpose of the Study:
- To resolve the structures of the mumps virus (MuV) L-P complex.
- To correlate distinct L-P conformations with viral RNA replication and transcription processes.
Main Methods:
- Cryogenic-electron microscopy (cryo-EM) was used to determine the structures of the MuV L-P complex.
- Comparative analysis with other nsNSV polymerase structures.
Main Results:
- Two distinct conformations of the MuV L-P complex were resolved.
- One conformation features a continuous RNA tunnel to the methyltransferase domain, suggesting a transcription state.
- The phosphoprotein (P) forms parallel tetramers around the large protein (L), with diverse origins of the P's L-binding X domain.
Conclusions:
- The study links specific L-P complex structures to nsNSV genome replication and transcription.
- A sliding model for polymerase complex movement along RNA templates is proposed.
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