Fighting HIV

HIV Infection Cycle

  1. HIV's attack helper T cells by attaching to the cell. via CD4 proteins in their cell membrane tl. Normally, these proteins bind to antigens to  activate of the helper T cells. This allows them access to the T4 lymphocyte.
  2. Once the virus has attached to a helper T cell, it injects its genetic information (as RNA) into the cell, along with the enzyme reverse transcriptase.
  3. Reverse transcriptase catalyzes the production of DNA from the viral RNA, making a DNA copy of the virus's genetic material. This DNA copy is capable of incorporating itself into the cell's genetic material, because it is now in the same form as the cell's chromosomes.  
    The step catalyzed by reverse transcriptase is one of the most important steps in the infection cycle.
  4. The viral DNA copy then enters the nucleus of the infected helper T cell, where it is incorporated into the cell's genetic material (i.e., the chromosomes).
  5. Using the cell's own DNA-replication mechanisms, the viral DNA replicates.
  6. Using the cell's mechanisms for producing proteins from the genetic information contained in DNA, many copies of the proteins needed by the virus are made from the replicated HIV DNA. As part of this step, RNA copies of the viral DNA are made.
  7. When they are first synthesized, the proteins are too long (containing extra fragments) to be assembled into new viruses. They must be cut to their proper size. The HIV enzyme protease, which is produced by the cell's biochemical machinery from the viral DNA incorporated into the cell's chromosomes, catalyzes the cutting of these proteins to their proper size.
  8. New HIV particles (viruses) are assembled inside the cell from the cut viral proteins and the viral RNA copies.
  9. Once assembled, the new viruses then burst out of the host cell (killing it) and invade new cells, continuing the infection.

Enzymes play a vital role in HIV's attack on helper T cells.
A DNA copy of the viral genome by reverse transcriptase (Step 3) and the cleavage of viral proteins (Step 7) by protease are two important processes catalyzed by enzymes.
Therefore, the enzymes reverse transcriptase and protease are major target sites for HIV-fighting drugs.
Any nucleotide analogue that can be inserted into the replicating DNA.
Thymine is the nucleotide of choice and has been made into AZT / Zidovudine/
 
By competitive inhibition of reverse transcriptase and or protease the viral ability to replicate is diminished thus not eliminating AIDS but controlling the activity of the HIV virus.
after http://www.chemistry.wustl.edu/~edudev/LabTutorials/HIV/DrugStrategies.html