Envelope refers to the virus envelopeprotein、PolysaccharideandlipidThe lipid bilayer membrane is also called capsule.The capsule mainly comes fromhost cellMembrane (phospholipid layer andMembrane protein）, but also contains some virusglycoprotein。The main function of the viral envelope is to help the virus enter the host cell.
Envelope refers to the lipid bilayer membrane composed of protein, polysaccharide and lipid, which is wrapped by the virus shell, also known asenvelope。The capsule mainly comes from the host cell membrane (phospholipid layer and membrane protein), but also contains some glycoproteins of the virus itself.It is generally believed that the envelope is a special structure that the virus carries when entering and leaving the host cell membrane.
function
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The main function of the viral envelope is to help the virus enter the host cell.First, the glycoprotein on the envelope surface recognizes and binds to the host surface receptor, then the viral envelope binds to the host cell membrane, and finally the viral capsid andViral genomeEnter the host and complete the infection process.
The enveloped virus is easier to enterhost cell, which helps the virus spread and reproduce in the host body, and improves the pathogenicity of the virus.The envelope plays an important role in recognizing host, invading host cells, and antigenicity of viruses.
Envelope virusThe molecular mechanism of membrane fusion can be attributed to the formation of polymers due to the conformational changes of membrane proteins, and the correct folding of membrane proteins may be the structural basis of lipid bilayer membrane fusion in vivo.
Mechanism research
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The first step of enveloped virus infecting cells is the adhesion and fusion of the viral envelope and the target cell membrane. The fusion results in the viral nucleocapsid entering the target cell, and the viral protein expressed by the infected cell is transported to the cell membrane. It can also promote the fusion of infected cells and uninfected cells, so that the viral infection continues to spread.It can be seen that the viral envelope plays an important role in the process of virus infection, so destroying the viral envelope is one of the keys to cut off the transmission route.[1]
WhenEnvelope virusInfectedhost cellThe envelope and the host cell membrane fuse each other, thus allowing virus particles to invade the host cell (the genetic material of the virus isNucleocapsid).It is known that this fusion process is mediated by the surface glycoprotein of the virus (by recognizing and binding the corresponding specific receptor), and this fusion process is the first pass for the infection of enveloping virus.
Early studies found that the envelope of the virus is related to the pathogenicity. After the envelope is dissolved and destroyed with a fat soluble solvent, the envelope virus loses its infectivity because there are envelope proteins encoded by one or several virus genes on the envelope, which are closely related to the infection of the virus.There are usually 1 to 3 kinds of envelope proteins on the surface of virus envelope, which mainly depends on different virofamilies, and most of them are glycosylated glycoproteins. More and more evidence shows that glycosylated modifications are extremely beneficial to viruses.[2]
The glycoprotein protruding on the viral envelope is a typical type I (or type II, rarely seen, such as HN of paramyxovirus) intact membrane protein, which is encoded by the virus itself and synthesized by infected cells, and is integrated intohost cellIn addition to its role in viral membrane fusion, many host immune responses target these glycosylated proteins, which is the main target of immune and vaccine research.
