Biology subjects
Publications and source records attributed to Alieva, R..
Nucleic acid aptamers are artificial recognition elements with high potential in biotechnology. Approaches for aptamer affinity optimization and activity regulation are required for aptamer-based nanodevices. Here thrombin aptamer affinity was increased by a single nucleotide modification with 7,8-dihydro-8-oxo-1,N6-ethenoadenine. Whereas a double modification makes the aptamer activity Ag+-dependent.
Non-canonical nucleic acid structures possess an ability to interact selectively with proteins, thereby exerting influence over various intracellular processes. Numerous studies indicate that genomic G-quadruplexes and i-motifs are involved in the regulation of transcription. These structures are formed temporarily during the unwinding of the DNA double helix; and their direct determination is a rather difficult task. In addition, i-motif folding is pH-dependent, with most i-motifs having low stability at neutral pH. However, some genomic i-motifs with long cytosine repeats were shown to be stable at pH 7.3, suggesting their functionality within the nucleus. Here we studied pH-dependent behavior of a model i-motif with flanking sequences that forms a duplex motif. Kinetic studies on bimodular structures with cytosine residues replaced with an environment-sensitive fluorescent label reveal the stabilization of the i-motif structure near the i-motif-duplex junction. These results highlight the importance of the natural environment of i-motifs for the correct assessment of their stability.