In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

Q: Coronavirus particles serve three fundamentally important functions in infection. The virion provides the means to deliver the viral genome across the plasma membrane of a host cell. The virion is also a means of escape for newly synthesized genomes. Lastly, the virion is a durable vessel that protects the genome on its journey between cells. This review summarizes the available X-ray crystallography, NMR, and cryoelectron microscopy structural data for coronavirus structural proteins, and looks at the role of each of the major structural proteins in virus entry and assembly. The potential wider conservation of the nucleoprotein fold identified in the Arteriviridae and Coronaviridae families and a speculative model for the evolution of corona-like virus architecture are discussed.

A: Supramolecular Architecture of the Coronavirus Particle
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Q: We performed experiments to determine the effect of PKR activation on respiratory syncytial virus (RSV) replication. We first determined that RSV infection activates PKR which induces the phosphorylation of eIF2α, resulting in the formation of host stress granules. We used RNA interference to decrease endogenous PKR levels. RSV replication was not altered in cells deficient for PKR expression. However, RSV-mediated stress granule formation was significantly reduced in PKR-knockdown cells. As an alternative method to block PKR activation, we used treatment with the kinase inhibitor 2-aminopurine (2-AP). We observed that 2-AP treatment significantly reduced viral replication. We also treated PKR-knockdown cells with 2-AP and inoculated with RSV. Under these conditions, 2-AP treatment diminished viral replication in the absence of PKR expression. These results suggest that PKR activation has a minimal effect on RSV replication and that the antiviral effect of 2-AP during RSV infection likely occurs via a PKR-independent mechanism.

A: Activation of protein kinase R is required for induction of stress granules by respiratory syncytial virus but dispensable for viral replication
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Q: The azurophilic granules of human neutrophils contain four a-defensins called human neutrophil peptides (HNPs 1-4). HNPs are tridisulfide-linked antimicrobial peptides involved in the intracellular killing of organisms phagocytosed by neutrophils. The peptides are produced as inactive precursors (proHNPs) which are processed to active microbicides by as yet unidentified convertases. ProHNP1 was expressed in E. coli and the affinity-purified propeptide isolated as two species, one containing mature HNP1 sequence with native disulfide linkages (''folded proHNP1'') and the other containing non-native disulfide linked proHNP1 conformers (misfolded proHNP1). Native HNP1, liberated by CNBr treatment of folded proHNP1, was microbicidal against Staphylococcus aureus, but the peptide derived from misfolded proHNP1 was inactive. We hypothesized that neutrophil elastase (NE), proteinase 3 (PR3) or cathepsin G (CG), serine proteases that co-localize with HNPs in azurophil granules, are proHNP1 activating convertases. Folded proHNP1 was converted to mature HNP1 by both NE and PR3, but CG generated an HNP1 variant with an N-terminal dipeptide extension. NE and PR3 cleaved folded proHNP1 to produce a peptide indistinguishable from native HNP1 purified from neutrophils, and the microbicidal activities of in vitro derived and natural HNP1 peptides were equivalent. In contrast, misfolded proHNP1 conformers were degraded extensively under the same conditions. Thus, NE and PR3 possess proHNP1 convertase activity that requires the presence of the native HNP1 disulfide motif for high fidelity activation of the precursor in vitro. Citation: Tongaonkar P, Golji AE, Tran P, Ouellette AJ, Selsted ME (2012) High Fidelity Processing and Activation of the Human a-Defensin HNP1 Precursor by Neutrophil Elastase and Proteinase 3. PLoS ONE 7(3): e32469.

A:
High Fidelity Processing and Activation of the Human a- Defensin HNP1 Precursor by Neutrophil Elastase and Proteinase 3
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