4P37: Crystal Structure Of The Megavirus Polyadenylate Synthase

Citation:
Abstract
Giant viruses from the Mimiviridae family replicate entirely in their host cytoplasm where their genes are transcribed by a viral transcription apparatus. mRNA polyadenylation uniquely occurs at hairpin-forming palindromic sequences terminating viral transcripts. Here we show that a conserved gene cluster both encode the enzyme responsible for the hairpin cleavage and the viral polyA polymerases (vPAP). Unexpectedly, the vPAPs are homodimeric and uniquely self-processive. The vPAP backbone structures exhibit a symmetrical architecture with two subdomains sharing a nucleotidyltransferase topology, suggesting that vPAPs originate from an ancestral duplication. A Poxvirus processivity factor homologue encoded by Megavirus chilensis displays a conserved 5'-GpppA 2'O methyltransferase activity but is also able to internally methylate the mRNAs' polyA tails. These findings elucidate how the arm wrestling between hosts and their viruses to access the translation machinery is taking place in Mimiviridae.
PDB ID: 4P37Download
MMDB ID: 128203
PDB Deposition Date: 2014/3/6
Updated in MMDB: 2015/04
Experimental Method:
x-ray diffraction
Resolution: 2.24  Å
Source Organism:
Similar Structures:
Biological Unit for 4P37: dimeric; determined by author and by software (PISA)
Molecular Components in 4P37
Label Count Molecule
Proteins (2 molecules)
1
Putative Poly(a) Polymerase Catalytic Subunit
Molecule annotation
1
Putative Poly(a) Polymerase Catalytic Subunit
Molecule annotation
Chemicals (14 molecules)
1
10
2
1
3
3
* Click molecule labels to explore molecular sequence information.

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