Highly fluorescent 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine 5'-triphosphate as an efficient substrate for DNA polymerases

Inhibitory Effect of 8-Halogenated 7-Deaza-2'-deoxyguanosine Triphosphates on Human 8-Oxo-2'-deoxyguanosine Triphosphatase, hMTH1, Activities

hMTH1 (8-oxo-2'-deoxyguanine triphosphatase) hydrolyzes oxidized nucleoside triphosphates; its presence is non-essential for survival of normal cells but is required for survival of cancer cells. In this study, 8-halogenated-7-deaza-2'-deoxyguanosine triphosphate (8-halogenated-7-deazadGTP) derivatives were synthesized. Interestingly, these triphosphates were poor substrates for hMTH1, but exhibited strong competitive inhibition against hMTH1 at nanomolar levels. This inhibitory effect is attributed to slower rate of hydrolysis, possibly arising from enzyme structural changes, specifically different stacking interactions with 8-halogenated-7-deazadGTP. This is the first example of using nucleotide derivatives to inhibit hMTH1, thus demonstrating their potential as antitumor agents.

Polymerase incorporation of a 2'-deoxynucleoside-5'-triphosphate bearing a 4-hydroxy-2-mercaptobenzimidazole nucleobase analogue

Here, we describe the enzymatic construction of a new larger base pair formed between adenine (A) and a 4-hydroxy-2-mercaptobenzimidazole (SB) nucleobase analogue. We investigated the enzymatic incorporation of 2'-deoxynucleoside-5'-triphosphate bearing a SB nucleobase analogue (dSBTP) into oligonucleotides (ONs) by DNA polymerases. dSBTP could be effectively incorporated at the site opposite a dA in a DNA template by several B family DNA polymerases. These findings provide new insights into various aspects of biotechnology, including the design of non-natural base pairs.

Synthesis of 2'-O-propargyl nucleoside triphosphates for enzymatic oligonucleotide preparation and "click" modification of DNA with Nile red as fluorescent probe

Uridine, adenosine, guanosine, and cytidine that carry a propargyl group attached to the 2'-oxygen were converted efficiently to the corresponding nucleoside triphosphates (pNTPs). Primer extension experiments revealed that pUTP, pATP, and pGTP can be successfully incorporated in oligonucleotides in the so-called 9°N and Therminator DNA polymerases. Most importantly, the ethynyl group as single 2'-modification of the enzymatically prepared oligonucleotides can be applied for postsynthetic labeling. This was representatively shown by PAGE analysis after the "click"-type cycloaddition with the fluorescent nile red azide. These results show that the 2'-position as one of the most important modification sites in oligonucleotides is now accessible not only for synthetic, but also for enzymatic oligonucleotide preparation.