RNA and DNA Diagnostics

We synthesized three chelate‐tethered purine ligands, having a Schiff base linkage at the N9 position, which resulted in the dipolar imine‐methoxyphenol adenine Schiff base HL1, the 2‐aminopurine Schiff base HL2, and the 2,6‐diaminopurine Schiff base HL3. These ligands selectively showed enhancement of the fluorescence of the zinc ions. The imine‐based compound HL1 chelated with zinc ions to give the discrete dimeric structure 1, a green fluorescent complex, which was again stabilized by purine–purine interactions to give a 1D polymeric structure. The ligands having a 6‐amino group, HL1 and HL3, have high quantum yield, which gives higher fluorescence enhancement of the free zinc ions in the HeLa cells. HL1 was localized in the cytoplasm and the nucleoli of the HeLa cells, which was confirmed by an RNase digestion test.

show abstract

DNA with Purine–Purine Base Pairs: Size and Position of Isoguanine and 8-Aza-7-deazaisoguanine Clickable Residues Control the Molecular Recognition of Guanine and 5-Aza-7-deazaguanine

Kondhare

Zhang

Leonard

et al. 2022

J. Org. Chem.

View full text Add to dashboard Cite

Purine–purine base pairs represent an alternative recognition system to the purine-pyrimidine pairing reported by Watson and Crick. Modified purines are the source for non-canonical interactions. To mimic dG–dC interactions, 2′-deoxyisoguanosine (1a) and 8-aza-7-deaza-2′-deoxyisoguanosine (2a) are used to construct base pairs with 2′-deoxyguanosine or 5-aza-7-deaza-2′-deoxyguanosine (dZ). This work reports the chemical functionalization of 1a and its shape mimic 2a in purine–purine base pairs. Clickable rigid ethynyl and more flexible octadiynyl side chain derivatives of 1a and 2a were synthesized. They were protected and converted into phosphoramidites. Building blocks were employed in the synthesis of base-modified 12-mer oligonucleotides with clickable side chains. Pyrene azide was clicked to the linkers. After hybridization, oligonucleotides with purine–purine base pairs were constructed with linkers and pyrene adducts at position-8 of isoguanine and at position-7 of 8-aza-7-deazaisoguanine. Recognition and stability of purine–purine base pairs were explored using T m values, thermodynamic data, and CD-spectroscopic changes. Side chains at position-7 of 8-aza-7-deazaisoguanine–guanine base pairs or with 5-aza-7-deazaguanine are well accommodated in DNA, whereas functionalization at 8-position of isoguanine makes the DNA unstable. Pyrene click adducts verified the observation. In conclusion, position-7 is the place of choice for purine–purine base pair functionalization.

show abstract

RNA and DNA Diagnostics

Cited by 7 publications

References 570 publications

Synthesis of Carbohydrate–Oligonucleotide Conjugates and Their Applications

Synthesis of Carbohydrate–Oligonucleotide Conjugates and Their Applications

Purine‐Based Fluorescent Sensors for Imaging Zinc Ions in HeLa Cells

DNA with Purine–Purine Base Pairs: Size and Position of Isoguanine and 8-Aza-7-deazaisoguanine Clickable Residues Control the Molecular Recognition of Guanine and 5-Aza-7-deazaguanine

Contact Info

Product

Resources

About