The LarB carboxylase/hydrolase forms a transient cysteinyl-pyridine intermediate during nickel-pincer nucleotide cofactor biosynthesis.

Enzymes possessing the nickel-pincer nucleotide (NPN) cofactor catalyze C2 racemization or epimerization reactions of α-hydroxyacid substrates. LarB initiates synthesis of the NPN cofactor from nicotinic acid adenine dinucleotide (NaAD) by performing dual reactions: pyridinium ring C5 carboxylation and phosphoanhydride hydrolysis. Here, we show that LarB uses carbon dioxide, not bicarbonate, as the substrate for carboxylation and activates water for hydrolytic attack on the AMP-associated phosphate of C5-carboxylated-NaAD.

Binding of anticancer drug daunomycin to parallel G-quadruplex DNA [d-(TTGGGGT)] leads to thermal stabilization: A multispectroscopic investigation.

Guanine rich DNA sequences form four stranded G-quadruplex structures found in telomeric DNA and oncogene promoters. Small molecules binding and stabilizing the G-quadruplex disrupt telomere maintenance and gene regulation, thereby limiting the proliferation of cancer cells. The anti-cancer drug daunomycin binds to both G-quadruplex DNA and duplex DNA.

Molecular Recognition of Parallel G-quadruplex [d-(TTGGGGT)]₄ Containing Telomeric DNA Sequence by Anticancer Drug Daunomycin: NMR-Based Structure and Thermal Stability.

The anticancer drug daunomycin exerts its influence by multiple strategies of action to interfere with gene functioning. Besides inhibiting DNA/RNA synthesis and topoisomerase-II, it affects the functional pathway of telomere maintenance by the telomerase enzyme. We present evidence of the binding of daunomycin to parallel-stranded tetramolecular [d-(TTGGGGT)]₄ guanine (G)-quadruplex DNA comprising telomeric DNA from by surface plasmon resonance and Diffusion Ordered SpectroscopY (DOSY).