Selenium-containing nucleosides are the building blocks of the Se-nucleic acids useful for structure-and-function study, drug discovery and for targeting nucleic acids and their protein complexes. However, chemical synthesis of these Se-containing nucleosides is labor-intensive and provides low overall yields. Thus, we decided to explore biocatalytic synthesis of the modified nucleosides (such as Se-nucleosides) by employing thermostable nucleoside phosphorylases from thermophilic microorganisms. We were surprised to discover that these enzymes can still recognize the nucleobases containing rather larger atoms, Se vs O atom. These enzymes also showed excellent adaptability to some modified purines with high substrate conversion (up to 97%).

含硒的核苷是硒核酸的组成部分，可用于结构和功能研究，药物发现以及靶向核酸及其蛋白复合物。然而，这些含硒的核苷的化学合成是劳动密集型的，并且总产率较低。因此，我们决定通过利用嗜热微生物的热稳定核苷磷酸化酶来探索修饰核苷（如硒核苷）的生物催化合成。我们惊讶地发现这些酶仍能识别出含有较大原子的Se或O原子的核碱基。这些酶还显示出对某些具有高底物转化率（高达97％）的修饰嘌呤的出色适应性。