Human immunodeficiency virus type 1 (HIV-1) requires the human tRNA(3)(Lys) as a reverse transcriptase (RT) primer. The annealing of 3' terminal 18 nucleotides of tRNA(3)(Lys) with the primer binding site (PBS) of viral RNA (vRNA) is crucial for reverse transcription. Additional contacts between the A rich (A-loop) region of vRNA and the anticodon domain of tRNA(3)(Lys) are necessary, which show the specific requirement of tRNA(3)(Lys). The importance of modified nucleosides, present in tRNA(3)(Lys), in giving stability to the primer-template complex has been determined in earlier experiments. It has been observed that the PNA oligomer targeted to PBS of vRNA destabilized the crucial interactions between primer and template due to which the reverse transcription is inhibited. Molecular dynamics simulations have been carried out to study the effect of modified nucleosides on the vRNA-tRNA(3)(Lys) complex stability and the destabilization effect of PNA oligomer on the vRNA-tRNA(3)(Lys)-PNA complex. The root-mean-square deviation, hydrogen bonding, tertiary interactions, and free energy calculations of the simulation data support the experimental results. The analyses have revealed the structural changes in PBS region of vRNA which might be another strong reason for the inability of RT binding to 7F helix for its normal functioning of reverse transcription.
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http://dx.doi.org/10.1080/07391102.2012.706076 | DOI Listing |
Org Biomol Chem
January 2025
Department of Chemistry, University of Turku, Henrikinkatu 2, 20500 Turku, Finland.
In this article, a neoacetalization-based method for post-SELEX modification of aptamers is introduced. Three modified quinine binding aptamer scaffolds were synthesized by replacing three different nucleosides of the binding site with a (2,3)-4-(methoxyamino)butane-1,2,3-triol residue. These aptamer scaffolds were incubated in different aldehyde mixtures with and without quinine, allowing the reversible formation of -methoxy-1,3-oxazinane (MOANA) nucleoside analogues through dynamic combinatorial chemistry.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
Modified nucleosides are vital in mRNA vaccines. We developed a contracted uridine analog, N1-hydantoinyl-ribose, HR, using steric shields to invert the regioselectivity of the classic Vorbrüggen reaction. We report synthetic routes and explore HR features such as acidity, stability, base pairing/stacking, and crystal/solution conformation compared to uridine.
View Article and Find Full Text PDFTheor Appl Genet
January 2025
CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia.
Zebularine-treated wheat uncovered a phenotype with characteristics of an epigenetically regulated trait, but major chromosomal aberrations, not DNA methylation changes, are the cause, making zebularine unsuitable for epigenetic breeding. Breeding to identify disease-resistant and climate-tolerant high-yielding wheats has led to yield increases over many years, but new hardy, higher yielding varieties are still needed to improve food security in the face of climate change. Traditional breeding to develop new cultivars of wheat is a lengthy process taking more than seven years from the initial cross to cultivar release.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, The College of Life Sciences, Sichuan University, 24 South Section 1, 1st Ring Road, Chengdu, Sichuan 610064, P.R. China.
Region-specific RNA modifications are crucial for advancing RNA research and therapeutics, including messenger RNA (mRNA)-based vaccines and immunotherapy. However, the predominant method, synthesizing regionally modified mRNAs with short single-stranded DNA (ssDNA) splints, encounters challenges in ligating long mRNA fragments due to the formation of RNA self-folded complex structures. To address this issue, we developed an efficient strategy using an easily obtained long double-stranded DNA (dsDNA) as a ligation splint after in situ denaturing, while parts of this dsDNA are the templates for transcribing mRNA fragments.
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