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3lt is an integrase of the HIV, the Human Immunodeficiency Virus. An integrase is an enzyme produced by a retrovirus to integrate its genetic material into the DNA of the infected cell. It is one of three enzymes of HIV, the others being the Reverse Transcriptase and the Protease.

Structural highlights

Function

HIV integrase is an enzyme required for the integration of viral DNA into the host genome. The process of integration can be divided into two sequential reactions. In the first one, named 3'-processing, the enzyme removes di- or trinucleotides from viral DNA ends to expose 3′-hydroxyls attached to the invariant CA dinucleotides. The second step is the insertion of the processed 3′-viral DNA ends into the host chromosomal DNA by a trans-esterification reaction. This is the strand transfer.

Structure

HIV-1 integrase is composed of three domains: the N-terminal (residues 1-49), the core domain (residues 50-212) and the C-terminal domain (residues 213-288). The core domain is responsible for the catalytic activity of the enzyme. It contains three acidic residues, the D,D-35-E motif which plays a key role in catalysis. The N-terminal domain includes the conserved HHCC motif, which binds zinc. The C-terminal domain is less well conserved. [1]

Representation of the three domain of the HIV integrase:

HIV integrase sequence:

Structure and role of the core domain in the integration

HIV

HIV stands for human immunodeficiency virus. It is a retrovirus virus that damages the cells in the immune system and weakens the ability to fight everyday infections and disease. Copied into DNA, HIV is inserted into the genome of the infected cell thanks to integrases. To replicate and diffuse himself it attacks the body’s immune system, specifically the CD4 cells (T cells), which help fight off infections. As soon as HIV enters an individual, it accumulates in these cells and forms reservoirs of latent viruses in a few days or even hours. These reservoirs persist for life.

No cure currently exists, but HIV can be controlled by using antiretroviral therapy or ART. It is a combination of antiretroviral drugs to maximally suppress the HIV virus and stop the progression of HIV disease. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS in just a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.[2]

Disease: AIDS

AIDS is the ultimate stage of infection with the human immunodeficiency virus. The word AIDS stands for for Acquired Immunodeficiency Syndrome. People with AIDS get an increasing number of severe illnesses, called opportunistic infections, because of there damaged immune system. You are considered to have progressed to AIDS when the number of your CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3). (In someone with a healthy immune system, CD4 counts are between 500 and 1,600 cells/mm3.) You are also considered to have progressed to AIDS if you develop one or more opportunistic illnesses, regardless of your CD4 count.[3]

References

https://www.hiv.gov/hiv-basics/overview/about-hiv-and-aids/what-are-hiv-and-aids https://www.hiv.gov/hiv-basics/overview/about-hiv-and-aids/what-are-hiv-and-aids