BIOCHEMISTRY OF HIV

This post covers the structure of HIV, how it infects a cell and how HIV spreads!

STRUCTURE:

• HIV are called Virions
• Virions is a virus particle consisting of:

1) an outer protein shell, (purple layer)                          
2) capsid (green dotted layer)

3) inner core of ribonucleic acid (yellow layer)

• The core confers infectivity& the capsid provides specificity to the virus!!

•  The virus is approx 100nm and has a icosahedral structure with 72 spikes found on the surface of the virus. The spikes are made up of 2 glycoproteins ( gp 120 & gp 41 )

WONDERING HOW HIV INFECTS OUR CELLS???????

Step 1: ENTRY

HIV can only replicate inside human cells! HIV attaches itself onto the surface protein CD4. The spikes on the surface of the virus sticks to CD4, causing the viral envelope to fuse with the cell membrane. The contents of the deadly virus are   then released into the                                                                         cell. 

Step 2: REVERSE TRANSCRIPTION & INTEGRATION

The primary host of HIV are white blood cells called T-helper cells. These cells are very important to our immune system as they activate responses of many other immune cells. When the T-helper cells are infected with HIV they die.

The body compensates for the loss of infected T cells by producing them in greater quantities. HIV enzyme, reverse transciptase converts RNA into DNA using the host cell's machinery to replicate itself.

The T4 is transformed into a biological factory producing new HIV. The T4 cell bursts releasing new virus into the blood stream. HIV then destroys the ability of the body to fight infection leading to illness and possible death

*** Protease Inhibitors can stop this process***

REFERENCES:

• http://www.britannica.com/EBchecked/topic/630143/virion
• http://www.avert.org/hiv-structure-and-life-cycle.htm
• http://health.howstuffworks.com/diseases-conditions/infectious/hiv-and-aids-dictionary2.htm