Integrase

Integrase

Structure of HIV-1 integrase catalytic core domain

Integrase is an enzyme produced by a retrovirus (such as HIV) that enables its genetic material to be integrated into the DNA of the infected cell. It is a key component in the life cycle of retroviruses, facilitating the insertion of viral DNA into the host genome, which is essential for viral replication and persistence.

Structure

Integrase is a multi-domain protein that typically consists of three main domains: the N-terminal domain, the catalytic core domain, and the C-terminal domain. The catalytic core domain is responsible for the enzyme's activity and contains the active site. This domain is highly conserved among different retroviruses.

Crystal structure of HIV-1 integrase

The N-terminal domain contains a zinc-binding motif that is important for the structural integrity of the enzyme. The C-terminal domain is involved in DNA binding and protein-protein interactions. The overall structure of integrase allows it to bind to both viral and host DNA, facilitating the integration process.

Function

Integrase catalyzes the insertion of viral DNA into the host cell's genome through a series of steps:

1. 3'-Processing: Integrase cleaves two nucleotides from the 3' ends of the viral DNA, creating reactive ends. 2. Strand Transfer: The enzyme then facilitates the joining of these processed viral DNA ends to the host DNA, integrating the viral genome into the host's. 3. Gap Repair: Host cell enzymes repair the gaps and mismatches at the integration site, completing the integration process.

Role in HIV

In the case of HIV, integrase is a critical enzyme for the virus's ability to establish a permanent infection. Once the viral RNA is reverse transcribed into DNA, integrase inserts this DNA into the host cell's genome, allowing the virus to hijack the host's cellular machinery to produce new viral particles.

Integrase

Inhibition and Drug Development

Due to its essential role in the viral life cycle, integrase is a prime target for antiretroviral drugs. Integrase inhibitors, such as raltegravir and dolutegravir, have been developed to block the activity of the enzyme, thereby preventing the integration of viral DNA into the host genome. These drugs are a crucial component of combination antiretroviral therapy (cART) for the treatment of HIV infection.

Related pages

• Retrovirus
• HIV
• Antiretroviral drug
• Reverse transcriptase