Virology and Bioinformatics from Virology.ca
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Virology and Bioinformatics from Virology.ca
Virus and bioinformatics articles with some microbiology and immunology thrown in for good measure
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Pairwise RNA secondary structure alignment with conserved stem pattern

"The regulatory functions performed by non-coding RNAs are related to their 3D structures, which are, in turn, determined by their secondary structures. Pairwise secondary structure alignment gives insight into the functional similarity between a pair of RNA sequences. We devised a method to approximate the true conserved stem pattern for a secondary structure pair, and constructed the alignment from it. Experimental results suggest that our method identified similar RNA secondary structures better than the existing tools, especially for large structures. It also successfully indicated the conservation of some pseudoknot features with biological significance. More importantly, even for large structures with arbitrary pseudoknots, the alignment can usually be obtained efficiently."

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Global Organization of a Positive-strand RNA Virus Genome

Global Organization of a Positive-strand RNA Virus Genome | Virology and Bioinformatics from Virology.ca | Scoop.it

The genomes of many important pathogenic viruses are made of RNA. These genomes encode viral proteins and contain regulatory sequences and structures. In some viruses, distant regions of the RNA genome can interact with each other via base pairing, which suggests that certain genomes may take on well-defined conformations. This concept was investigated using a tombusvirus RNA genome that contains several long-range RNA interactions. The results of microscopic and biochemical analyses indicated a compact genome conformation with structured regions radiating from a central core. The structural model was compatible with some, but not all, long-range interactions, suggesting that the genome is a dynamic molecule that assumes different conformations. The analysis also revealed new structural features of the genome, some of which were shown to be functionally relevant. This study advances our understanding of the role played by global structure in virus genome function and provides a model to further investigate its in role virus reproduction. We anticipate that organizational principles revealed by this investigation will be applicable to other viruses.

  
Ed Rybicki's insight:

Plant viruses rule OK...!  Or biophysical investigations of their genomes do.  Seriously, this is an impressive piece of work, that points up the fact that information content of a genome definitely does not stop with the sequence.

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MicrobiologyBytes » Structure of Ebola virus [video]

MicrobiologyBytes » Structure of Ebola virus [video] | Virology and Bioinformatics from Virology.ca | Scoop.it

A video walk-through of the paper

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Herpes Virus Genome, The Pressure Is On

Abstract

 

Herpes simplex virus type 1 (HSV-1) packages its micrometers-long double-stranded DNA genome into a nanometer-scale protein shell, termed the capsid. Upon confinement within the capsid, neighboring DNA strands experience repulsive electrostatic and hydration forces as well as bending stress associated with the tight curvature required of packaged DNA. By osmotically suppressing DNA release from HSV-1 capsids, we provide the first experimental evidence of a high internal pressure of tens of atmospheres within a eukaryotic human virus, resulting from the confined genome. Furthermore, the ejection is progressively suppressed by increasing external osmotic pressures, which reveals that internal pressure is capable of powering ejection of the entire genome from the viral capsid. Despite billions of years of evolution separating eukaryotic viruses and bacteriophages, pressure-driven DNA ejection has been conserved. This suggests it is a key mechanism for viral infection and thus presents a new target for antiviral therapies.

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Latest Insights on Adenovirus Structure and Assembly

Latest Insights on Adenovirus Structure and Assembly | Virology and Bioinformatics from Virology.ca | Scoop.it

Adenovirus (AdV) capsid organization is considerably complex, not only because of its large size (~950 Å) and triangulation number (pseudo T = 25), but also because it contains four types of minor proteins in specialized locations modulating the quasi-equivalent icosahedral interactions. Up until 2009, only its major components (hexon, penton, and fiber) had separately been described in atomic detail. Their relationships within the virion, and the location of minor coat proteins, were inferred from combining the known crystal structures with increasingly more detailed cryo-electron microscopy (cryoEM) maps. There was no structural information on assembly intermediates. Later on that year, two reports described the structural differences between the mature and immature adenoviral particle, starting to shed light on the different stages of viral assembly, and giving further insights into the roles of core and minor coat proteins during morphogenesis [1,2]. Finally, in 2010, two papers describing the atomic resolution structure of the complete virion appeared [3,4]. These reports represent a veritable tour de force for two structural biology techniques: X-ray crystallography and cryoEM, as this is the largest macromolecular complex solved at high resolution by either of them. In particular, the cryoEM analysis provided an unprecedented clear picture of the complex protein networks shaping the icosahedral shell. Here I review these latest developments in the field of AdV structural studies.

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