G-quadruplex stabilization in the ions and maltose transporters inhibit Salmonella enterica growth and virulence

Neha Jain; Subodh Kumar Mishra; Uma Shankar; Arpita Tawani; Ankit Jaiswal; Tarun Kumar Sharma; Prashant Kodgire; Amit Kumar

In order to understand the role of SE-PGQs in the cytotoxic effect of 9-amino acridine, binding affinity of 9-amino acridine with these SE-PGQs were analyzed by performing CD Melting studies. An increase in the melting temperature (ΔT m~8 .5°C) was observed upon addition of 9-amino acridine when compared with alone SE-PGQs. This indicated that 9-amino acridine increased the thermodynamic stability of SE-. CC-BY 4.0 International license is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/357046 doi: bioRxiv preprint PGQs (Fig 8) . Further, we employed a Taq polymerase PCR stop assay to investigate whether 9-amino acridine complex formation with SE-PGQs, make it possible to stop the movement of polymerase replication machinery or not. In order to investigate this hypothesis, we incubated PCR reaction mixture with 9-amino acridine in a concentration dependent manner and then performed PCR amplification. We observed diminished intensity of bands with increase in concentration of 9-amino acridine, however, in the absence of the 9 amino acridine the band intensity was maximum indicated that the Taq polymerase were able to extend the SE-PGQs motifs. It shows that binding of the 9-amino acridine to the SE-PGQs motif stabilized the G-quadruplex structure and inhibited the movement of replication machinery over the untreated SE-PGQs. On the contrary, when mutant PGQs lacking G-tract were used as a DNA template, 9-amino acridine was not able to bind and thus, could not inhibit the movement of Taq polymerase and produced a PCR product in the reaction (Fig 9) .