Question

1.describe phage induced proteins tell me about them? in viruse replication

Answer 1

The phage induced proteins are those proteins which are produced during the viral replication. The virus is unable to replicate on its own and require a host cell within which it replicates and reproduces as they lack the enzymes which are essential for their reproduction. The phage proteins helps the virus to enter the host cell through binding to the receptors present on the cell wall. There are specific receptors which are present on the surface of the host cell and the phage protein recognize these receptors and bind to the same. Here are the steps of virus replication:-

• Adsorption – This is the first step of virus replication where the virus particle or phage attach to the host cell via the process of adsorption. The phage proteins recognize receptors on surface of host cell like bacteria. Each of the virus particles has different and specific receptors that they are able to recognize and bind to.
• Penetration – This is the first step of virus replication initiated by the mechanism of penetration. The virus generally uses the phage proteins to bind to the receptors and with help of enzymes like lysozyme degrade the cell wall. After the cell wall is degraded, the virus injects its genome in the cytoplasm of the host cell. This process is called penetration and the empty capsid remain outside.
• Phage component synthesis – After the genome of the virus is injected into the host cell, it initiates the synthesis of the phage proteins. These proteins enables the incorporation of the phage genome into the host DNA and hence it initiates the genome replication. There are other phage induced proteins which helps in the replication of the phage DNA. The phage DNA which are newly produced initiates the production of late proteins which helps in the production of phage head and tail. Hence, the phage proteins help in the production of phage DNA along with synthesis of phage components like the head and tail.
• Assembly of phage components – The production of the head and tail along with phage DNA is separate but in order to form the phage, the components need to be assembled together. The capsid protein leads to the production of the head and it helps in packing the viral DNA in its condensed form with it. The tail is at last attached and assembled to head and it forms progeny viral particles.
• The last step is lysis or release of the newly formed virus or phage. The production of phage enzymes breaks the cell wall and hence it tends to release out all the newly formed virions.