Benzoquinoquinoxaline Derivatives Stabilize and Cleave H-DNA and Repress Transcription Downstream of a Triplex-forming Sequence

A Distinct Triplex DNA Unwinding Activity of ChlR1 Helicase

“…Benzoquinoquinoxaline (BQQ) Treatment-Cells were treated with BQQ as described (44). Briefly, ChlR1-depleted and siRNA control cells and FANCJ Ϫ/Ϫ and FANCJ ϩ/ϩ cells were grown on coverslips overnight at 37°C in DMEM supplemented with 10% fetal bovine serum and penicillin/streptomycin (100 units/ml each) media and then incubated with BQQ (final concentration of 8 M) or the same amount of DMSO as vehicle control at 37°C overnight (12 h).…”

“…A Triplex Stabilizing Compound BQQ Inhibits ChlR1 Unwinding-BQQ is a highly specific triplex-stabilizing compound that is able to bind both pyrimidine and purine motif triple-helix structures (44,(51)(52)(53). To confirm the stabilizing ability of BQQ on our triplex DNA structures, we used flush and plasmid triplex DNA to verify whether BQQ can prevent these DNA substrates from unwinding by ChlR1.…”

Structure‐Specific Recognition of Friedreich's Ataxia (GAA)n Repeats by Benzoquinoquinoxaline Derivatives

“…[29][30][31][32] BQQ is cell permeable, and we have shown that the compound binds and stabilizes H-DNA structures formed in plasmids in growing Escherichia coli cells. [33] Furthermore, we have converted BQQ to a triplex-specific cleaving agent (BQQ-OP, Figure 1 B) by conjugation to a 1,10-phenanthroline derivative. [30] BQQ-OP causes DNA double strand cleavage specifically at the site of formation of a triple helix, and we have previously demonstrated the ability of BQQ-OP to probe H-DNA formation in plasmids in vitro.…”

“…[30] BQQ-OP causes DNA double strand cleavage specifically at the site of formation of a triple helix, and we have previously demonstrated the ability of BQQ-OP to probe H-DNA formation in plasmids in vitro. [33] To enable structure-and sequence-specific targeting of the non-B-DNA structures involved in frataxin gene silencing, it is important to primarily analyze the different triplex motifs within sticky DNA that may form at pathological (GAA) n repeats. To this end, we have examined (GAA) n -specific recognition and binding by BQQ derivatives and sequence-complementary binding by using single-stranded oligonucleotides.…”

Synthesis and Structure of Dimeric Copper (I) Complex from Bis[(2,2’)-dimethyl 2,2’-(1,10-phenanthroline-2,9-diyl) bis(methan-1-yl-1-ylidene)-bis(hydrazinecarbo dithioate)]

“…The key feature of 1,10-phenanthroline is π-electron deficient nitrogen which stabilizes various metal complexes in lowered oxidation states [4]. The copper/phen complexes are able to interact and cleave the DNA/RNA backbone [5,6]. Recently, it has been found that copper(II) complexes of ferrocene(Fc)-conjugated reduced Schiff base of L-tyrosine are cytotoxic in HeLa (human cervical cancer) and MCF-7 (human breast cancer) [7].…”