Unveiling the unusual i-motif-derived architecture of a DNA aptamer exhibiting high affinity for influenza A virus.

Non-canonical nucleic acid structures play significant roles in cellular processes through selective interactions with proteins. While both natural and artificial G-quadruplexes have been extensively studied, the functions of i-motifs remain less understood. This study investigates the artificial aptamer BV42, which binds strongly to influenza A virus hemagglutinin and unexpectedly retains its i-motif structure even at neutral pH.

Rapid kinetics of H transport by membrane pyrophosphatase: Evidence for a "direct-coupling" mechanism.

Stress resistance-conferring membrane pyrophosphatase (mPPase) found in microbes and plants couples pyrophosphate hydrolysis with H transport out of the cytoplasm. There are two opposing views on the energy-coupling mechanism in this transporter: the pumping is associated with either pyrophosphate binding to mPPase or the hydrolysis step. We used our recently developed stopped-flow pyranine assay to measure H transport into mPPase-containing inverted membrane vesicles on the timescale of a single turnover.

Na Translocation Dominates over H-Translocation in the Membrane Pyrophosphatase with Dual Transport Specificity.

Cation-pumping membrane pyrophosphatases (mPPases; EC 7.1.3.

Kinetics of i-motif folding within the duplex context.

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.