Rodriguez Andrew A, Cedillo Isaiah, McPherson Andrew K
Ionis Pharmaceuticals, Inc., 2855 Gazelle Ct., Carlsbad, CA 92010, USA.
Ionis Pharmaceuticals, Inc., 2855 Gazelle Ct., Carlsbad, CA 92010, USA.
Bioorg Med Chem Lett. 2016 Aug 1;26(15):3468-71. doi: 10.1016/j.bmcl.2016.06.042. Epub 2016 Jun 18.
The acetyl capping reaction used throughout solid phase oligonucleotide synthesis is meant to minimize n-1 deletionmer impurities by terminating sequences that fail to couple to a phosphoramidite. However, the reaction is also responsible for the formation of a number of impurities. One capping-related impurity has an additional mass of 98amu from the parent oligonucleotide. The n+98 amu impurity was found to result from modification of an adenine nucleobase. The structure of the impurity was determined by preparation of an oligonucleotide enriched in n+98 amu, enzymatic digestion to individual nucleosides, isolation of the pure nucleoside+98 amu species, crystallization, and X-ray crystallographic analysis. The n+98 amu impurity is an oligonucleotide in which one adenine residue has been converted to 5-amino-4-pyrimidinylimidazole. The mechanism of formation of the impurity was investigated, and a mechanism is proposed.
在固相寡核苷酸合成过程中使用的乙酰封端反应旨在通过终止未能与亚磷酰胺偶联的序列来尽量减少n-1缺失mer杂质。然而，该反应也会导致多种杂质的形成。一种与封端相关的杂质相对于亲本寡核苷酸有额外98amu的质量。发现n + 98 amu杂质是由腺嘌呤核苷酸碱基的修饰产生的。通过制备富含n + 98 amu的寡核苷酸、酶切为单个核苷、分离纯的核苷 + 98 amu物种、结晶和X射线晶体学分析来确定杂质的结构。n + 98 amu杂质是一种寡核苷酸，其中一个腺嘌呤残基已转化为5-氨基-4-嘧啶基咪唑。对杂质的形成机制进行了研究，并提出了一种机制。
