THE VIRUS ON IT'S OWN

Structure:

This virus is one of the largest phages at approximately 90nm wide and 200nm long. It consists of protein coat, a genome, tail fibers and a base plate. Its tail fibers allow attachment to a host cell, and the T4’s tail is hollow so that it can pass its nucleic acid to the cell it is infecting during attachment.

:http://www.bacteriophagetherapy.info/ECF40946-8E2F-4890-9CA6-D390A26E39C1/Images/Phage-Solo1.jpg)

How the virus attaches to its host:





The example that I am going to use is how this virus attaches to an E. coli. The T4 Phage initiates infection of an E. coli bacterium by recognizing cell surface receptors of the host with its long tail fibers. A recognition signal is sent through the Long tail fibers to the baseplate. This unravels the short tail fibers that bind irreversibly to the E. coli cell surface. The baseplate changes conformation and the tail sheath contracts causing GP5 at the end of the tail tube to puncture the outer membrane of the cell. The lysozyme domain of GP5 is activated and degrades the periplasmic peptidogliycan layer. The remaining part of the membrane is degraded and DNA from the head of the Phage can travel through the tail tube and enter the E. coli.

(Picture URL:http://media-2.web.britannica.com/eb-media/43/4943-004-5350FC7A.gif)





The process of replication:


T4 bacteriophage reproduce with the lyctic cycle. The bacteriophage connects to the surface of the host, punctures the cell with its injection tube, and then injects it own genetic materials. The genetic information subverts the host cell's normal operation and sets the cell's biosynthetic machinery to work creating many of the virus' cells. These newly created viruses escape from the cell and then float about until one happens to come in contact with a new host cell.





http://www.apsnet.org/online/feature/phages/image/phage6sm.jpg








3 sources:

http://biology.kenyon.edu/BMB/Chime2/2002/T4injector/FRAMES/captxt.htm
This site contained many useful facts about the replication and the structure of the bacteriophage virus I am studying.

http://www.hybridmedicalanimation.com/anim_bacteriophage.html
This site had not much information but it did have a good video on how the virus attacks its host cell which was quite useful.

http://www.ncbi.nlm.nih.gov/pubmed/12626685
This site had some interesting information about the virus and some of its characteristics but it did not give a vivid understanding of its structure and replication.