Nebularine is a naturally occurring nucleoside, which inhibits mouse Sarcoma 180 and mycobacteria. Studies indicate that Nebularine functions by inhibiting enzymes such as adenine deaminase. In addition, Nebularine can be used to analyze structure determinants of DNA that are recognized by DNA repair enzymes. These studies show that Nebularine can also be used to locate triple helices at G-C sequences. Nebularine can act as a universal base, which can bind to all four of the nucleosides of DNA, with a greater tendency binding to Thymine. Furthermore, Nebularine cellular uptake in mice can be reduced by the nucleoside transport inhibitor, nitrobenzylthioinosine.