Writing through catalysis: A tape-reading molecular catalyst

1936年，艾伦·图灵发表了一个抽象计算自动机的概念。现在被称为“图灵机”，他的提议设想了一种设备，其特点是一个“头”，可以在沿着磁带移动的同时读写符号。这个有影响力的思想实验引发了计算机科学的发展。虽然现代计算机使用不同的设计，采用随机存取存储器，图灵的“自动机器”的相似之处是惊人的信息处理在生物学（阅读和信息的核糖体，例如。最近，Leigh小组报道了一种人造分子机器，该机器通过化学燃料沿着沿着分子带定向传输，改变阅读头的构象以响应其在沿着途中遇到的带上的手性中心。构象变化导致头部的圆二色性响应的变化，因此分子带上的符号序列可以根据变化的CD响应作为一串数据读出（280 nm处的+ve Cotton效应对应于数字+1; -ve Cotton效应对应于-1，无Cotton效应对应于0）。这个项目将寻求通过催化将这个概念扩展到信息的书写，利用构象的变化来改变阅读头在沿着轨道移动时的不对称催化的手性。我们将首先通过逐步操作来研究这个概念（例如，与Trost样配体，如下所述），并最终将其扩展到具有编码序列信息的聚合物的合成，一种类似于核糖体所完成的任务。人工催化剂的发展，当它沿着一条信息链定向移动时，它会改变催化转化的立体化学结果。编码轨道将是人工分子机械和催化领域的里程碑式成就。它将使分子信息从一种形式（原始磁带）转换为另一种形式。这类似于核糖体的功能，但在一个完全人工的系统中，不限于肽，并且以立体化学而不是核苷酸密码子的阅读为特征。在这个项目中获得的知识将在不同领域产生影响。除了可能改进合成催化剂的设计外，这些结果还可能导致新的人工酶样催化剂的设计。

In 1936 Alan Turing published a concept for an automatic machine for abstract computing. Nowadays called a 'Turing machine', his proposal envisaged a device that featured a 'head' that could read and write symbols while moving along a tape. This influential thought experiment sparked the development of computer science. Although modern computers use a different design that employs random access memory, the resemblance of Turing's 'automatic machine' to information processing in biology is striking (the reading and writing of information by the ribosome, for example. Recently, the Leigh group reported an artificial molecular machine that is transported directionally along a molecular tape by chemical fuelling, changing the conformation of the reading head in response to chiral centres on the tape it encounters along the way. The conformational change results in changes to the circular dichroism response of the head, and so the sequence of symbols on the molecular tape can be read out as a string of data according to the changing CD response (+ve Cotton effect at 280 nm corresponds to the digit +1; -ve Cotton effect to -1, no Cotton effect to 0). This project will seek to extend this concept to the writing of information through catalysis, using the change in conformation to alter the handedness of asymmetric catalysis by the reading head as it moves along the track. We will first investigate this concept through step-wise operations (e.g. with Trost-like ligands, as depicted below) and, ultimately, extend it to the synthesis of polymers with encoded sequence information, a task analogous to that performed by the ribosome.The development of an artificial catalyst that changes the stereochemical outcome of catalytic transformations as it moves directionally along an information-encoded track would be a landmark achievement for the fields of both artificial molecular machinery and catalysis. It would enable the translation of molecular information from one form (the original tape) to another. This would be analogous to the function performed by the ribosome, but in a wholly artificial system not limited to peptides and featuring the reading of stereochemistry rather than nucleotide codons. The knowledge gained in this project will have impact in different areas. In addition to potentially improving the design of synthetic catalysts, the results may lead to the design of new, artificial, enzyme-like catalysts.