My Association with HIV Reverse Transcriptase

 My Association with HIV Reverse Transcriptase:

Just saw on linkedin: Dr. David Baltimore, Nobel prize winner  & co-discoverer of HIV-1 Reverse Transcriptase, passes away at 87.

The central dogma of molecular biology involves DNA-the molecule which contains genes, that is    transcribed into RNA, which is eventually made into protein. However an enzyme (proteins that speed up or catalyze reactions within cells) in human immunodeficiency virus (HIV) reverse transcribed RNA into DNA. This went against the central dogma of molecular biology. Researchers Howard Temin & David Baltimore were awarded the Nobel prize for this discovery (1975) , https://www.nobelprize.org/prizes/medicine/1975/baltimore/facts/  

My tryst with HIV Reverse Transcriptase began  in 1999, when I joined Prof. Monica Roth's Laboratory as a graduate research fellow, post a successful laboratory rotation. This was in the Molecular Biosciences program jointly hosted by Rutgers-UMDNJ, New Jersey USA. I picked a project which involved HIV-1 Reverse Transcriptase. It was a protein modeling project.

HIV-1 Reverse Transcriptase has two functional domains: a polymerase which makes the double stranded DNA polymer and an Rnase H domain which breaks down the RNA component (derived from HIV and also the tRNA primer) of the RNA-DNA hybrids, so as to form a full double stranded DNA genome ,that can integrate into the host cell DNA and remain as a provirus. Prof. Roth had designed a polypeptide minus the polymerase domain, so as to  screen for inhibitors of HIV-1 RNaseH enzyme only.

It took 6 months to clone the polypeptide. This was followed by purification  and testing activity of this polypeptide on hybrid RNA-DNA substrates, in the presence of manganese, which took two and a half years. These findings culminated in a paper in 2004, and the design made to the cover of the  journal: Protein Engineering Design & Selection (PEDS):

https://academic.oup.com/peds/article-abstract/17/7/581/1553405

This designed polypeptide formed the precursor to an RnaseH  polypeptide that functioned in the physiological cation, Magnesium, and a subsequent paper from Prof. Roths laboratory.

Interestingly , when I co-wrote a book chapter , on DNA viruses containing reverse transcriptases;

https://www.taylorfrancis.com/chapters/edit/10.1201/9781003369349-15/dna-viruses-containing-reverse-transcriptase-sonali-sengupta-baibaswata-nayak ,we included the Baltimore classification of viruses.

So Prof. David Baltimore has indirectly played an invaluable role in catalysing my growth as a researcher , and this blogpost is in memory of this great scientist. I bow to him with humility.