What is the purpose of the hemagglutinin surface protein for influenza viruses?

The hemagglutinin glycoprotein of influenza virus has important functions in the initiation of infection: it mediates adsorption of the virus particles to cell surface receptors and is responsible for the subsequent uncoating of the virus by a process of fusion between viral and host membranes.

What is the particle size of influenza virus?

It is concluded that influenza virus activity is not associated with material having a particle diameter of about 10 mmicro, but is associated solely with material having a sedimentation constant of about 600 S and hence a probable particle diameter of about 70 mmicro.

Can influenza get different HA or NA proteins during antigenic shift?

Another type of change is called “antigenic shift.” Shift is an abrupt, major change in a flu A virus, resulting in new HA and/or new HA and NA proteins in flu viruses that infect humans. Antigenic shift can result in a new flu A subtype.

Can Size Exclusion Chromatography be used for separation of viral particles?

Though size exclusion chromatography (SEC) has been the primary tool for separating aggregates of molecules, it is generally not appropriate for fractionating viruses because viruses and their aggregates are subject to shearing degradation by the stationary phase.

What type of protein is hemagglutinin?

Structure. The hemagglutinin has a cylindrical shape and is a small protein (13 nanometers long). It’s a glycoprotein formed by three identical monomer subunits, together known as a homotrimer.

What size particle does a N95 mask filter?

N95 respirators made by different companies were found to have different filtration efficiencies for the most penetrating particle size (0.1 to 0.3 micron), but all were at least 95% efficient at that size for NaCl particles.

What is correct about the antigenic shift in flu virus?

Antigenic shift is a more major change in the influenza virus. This shift typically occurs when a human flu virus crosses with a flu virus that usually affects animals (such as birds or pigs). When the viruses mutate, they shift to create a new subtype that is different from any seen in humans before.

What is the size of SARS CoV 2 virus?

SARS-CoV-2 is an enveloped virus ≈0.1 μm in diameter, so N95 masks are capable of filtering most free virions, but they do more than that. How so? Viruses are often transmitted through respiratory droplets produced by coughing and sneezing.

How many residues are in influenza hemagglutinin protein?

328 residues
The HA1 subunit (328 residues) is an elongate structure reaching from the N-terminus at the viral membrane end of the molecule along the stem of the subunit before forming a globular tip.

What is the size of SARS-CoV-2 virus?

What virus has the largest genome?

We recently described Megavirus chilensis, a giant virus isolated off the coast of Chile, also replicating in fresh water acanthamoeba. Its 1,259,197-bp genome encodes 1,120 proteins and is the largest known viral genome.

What is the H and N in influenza?

Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N).

Why does antigenic shift only occur in influenza A?

Antigenic shift, however, occurs only in influenza A because it infects more than just humans. Affected species include other mammals and birds, giving influenza A the opportunity for a major reorganization of surface antigens.

Which is worse antigenic shift or drift?

Because the genes in the resulting virus are dramatically different, this is called antigenic shift. Antigenic shift is more concerning than antigenic drift. Antigenic shift can produce a version of influenza virus that no person’s immune system has antibodies to protect against.

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