what does the enzyme called reverse transcriptase (found in HIV) do?
Since this is not my area of expertise, I searched Google under the key words "HIV 'reverse transcriptase'" to get these possible sources:
http://en.wikipedia.org/wiki/Reverse_transcriptase
http://www.cellsalive.com/hiv2.htm
http://www.biochem.ucl.ac.uk/bsm/xtal/teach/repl/rt.html
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=307744
http://www.pnas.org/cgi/content/abstract/210392297v1
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.
Reverse transcriptase is an enzyme that plays a critical role in the replication cycle of retroviruses, such as Human Immunodeficiency Virus (HIV). It catalyzes the reverse transcription process, which involves the synthesis of viral DNA from the viral RNA genome.
To understand how reverse transcriptase works, let's break down the steps involved:
1. Binding: First, the reverse transcriptase enzyme binds to the viral RNA genome inside the host cell.
2. RNA degradation: Reverse transcriptase possesses both RNAase H and DNA polymerase activities. The RNAase H activity allows it to degrade the viral RNA in the RNA:DNA hybrid molecule, leaving a small RNA primer intact.
3. DNA synthesis: Using the remaining RNA primer as a starting point, reverse transcriptase initiates the synthesis of a complementary DNA strand, known as the minus strand or cDNA. It uses the viral RNA genome as a template to synthesize the complementary DNA strand.
4. RNase H activity: As the synthesis progresses, reverse transcriptase also degrades the remaining RNA fragments using its RNAase H activity.
5. Reverse transcription: Once the cDNA synthesis is complete, reverse transcriptase uses the newly synthesized minus strand DNA as a template to synthesize the second DNA strand, known as the plus strand or (+) DNA.
6. Termination: Finally, reverse transcriptase reaches the end of the viral RNA template and completes the synthesis of the double-stranded DNA molecule.
The reverse transcription process allows HIV to convert its RNA genome into DNA, which can then integrate into the host cell's DNA. This integration allows the virus to persist within the host, leading to the chronic infection characteristic of HIV/AIDS.
Understanding the role of reverse transcriptase in the HIV life cycle is crucial for developing antiretroviral drugs that target this enzyme, inhibiting its activity and effectively blocking viral replication.