Amalian J-A, Al Ouahabi A, Cavallo G, König N F, Poyer S, Lutz J-F, Charles L
Aix Marseille Univ, CNRS, UMR 7273, Institut de Chimie Radicalaire, 13397 Marseille Cedex 20, France.
CNRS, Institut Charles Sadron UPR22, Université de Strasbourg, 23 rue du Loess, 67034, Strasbourg Cedex 2, France.
J Mass Spectrom. 2017 Nov;52(11):788-798. doi: 10.1002/jms.3947.
Digital polymers are monodisperse chains with a controlled sequence of co-monomers, defined as letters of an alphabet, and are used to store information at the molecular level. Reading such messages is hence a sequencing task that can be efficiently achieved by tandem mass spectrometry. To improve their readability, structure of sequence-controlled synthetic polymers can be optimized, based on considerations regarding their fragmentation behavior. This strategy is described here for poly(phosphodiester)s, which were synthesized as monodisperse chains with more than 100 units but exhibited extremely complex dissociation spectra. In these polymers, two repeating units that differ by a simple H/CH variation were defined as the 0 and 1 bit of the ASCII code and spaced by a phosphate moiety. They were readily ionized in negative ion mode electrospray but dissociated via cleavage at all phosphate bonds upon collisional activation. Although allowing a complete sequence coverage of digital poly(phosphodiester)s, this fragmentation behavior was not efficient for macromolecules with more than 50 co-monomers, and data interpretation was very tedious. The structure of these polymers was then modified by introducing alkoxyamine linkages at appropriate location throughout the chain. A first design consisted of placing these low dissociation energy bonds between each monomeric bit: while cleavage of this sole bond greatly simplified MS/MS spectra, efficient sequencing was limited to chains with up to about 50 units. In contrast, introduction of alkoxyamine bonds between each byte (i.e. a set of eight co-monomers) was a more successful strategy. Long messages (so far, up to 8 bytes) could be read in MS experiments, where single-byte containing fragments released during the first activation stage were further dissociated for sequencing. The whole sequence of such byte-truncated poly(phosphodiester)s could be easily re-constructed based on a mass tagging system which permits to determine the original location of each byte in the chain. Copyright © 2017 John Wiley & Sons, Ltd.
数字聚合物是具有可控共聚单体序列的单分散链，这些共聚单体序列被定义为字母表中的字母，用于在分子水平上存储信息。因此，读取此类信息是一项测序任务，可通过串联质谱法高效完成。为了提高其可读性，可以基于对其碎片化行为的考虑，优化序列控制的合成聚合物的结构。本文针对聚磷酸二酯描述了这一策略，聚磷酸二酯被合成为具有100多个单元的单分散链，但表现出极其复杂的解离光谱。在这些聚合物中，两个仅相差一个简单的H/CH变化的重复单元被定义为ASCII码的0和1位，并由一个磷酸基团隔开。它们在负离子模式电喷雾中很容易离子化，但在碰撞激活时会通过所有磷酸键的断裂而解离。尽管这种碎片化行为能够实现数字聚磷酸二酯的完整序列覆盖，但对于具有50多个共聚单体的大分子来说效率不高，并且数据解释非常繁琐。然后通过在整个链的适当位置引入烷氧基胺键来修饰这些聚合物的结构。第一种设计是在每个单体位之间放置这些低解离能键：虽然仅该键的断裂极大地简化了MS/MS光谱，但高效测序仅限于最多约50个单元的链。相比之下，在每个字节（即一组八个共聚单体）之间引入烷氧基胺键是一种更成功的策略。在MS实验中可以读取长信息（到目前为止，长达8个字节），其中在第一个激活阶段释放的含单字节片段会进一步解离以进行测序。基于质量标记系统可以轻松重建此类字节截断的聚磷酸二酯的完整序列，该系统允许确定链中每个字节的原始位置。版权所有© 2017约翰威立父子有限公司。
