Fraccia Tommaso P, Smith Gregory P, Zanchetta Giuliano, Paraboschi Elvezia, Yi Youngwoo, Walba David M, Dieci Giorgio, Clark Noel A, Bellini Tommaso
Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, via Fratelli Cervi 93, I-20090 Segrate, Milan, Italy.
Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, USA.
Nat Commun. 2015 Mar 10;6:6424. doi: 10.1038/ncomms7424.
It has been observed that concentrated solutions of short DNA oligomers develop liquid crystal ordering as the result of a hierarchically structured supramolecular self-assembly. In mixtures of oligomers with various degree of complementarity, liquid crystal microdomains are formed via the selective aggregation of those oligomers that have a sufficient degree of duplexing and propensity for physical polymerization. Here we show that such domains act as fluid and permeable microreactors in which the order-stabilized molecular contacts between duplex terminals serve as physical templates for their chemical ligation. In the presence of abiotic condensing agents, liquid crystal ordering markedly enhances ligation efficacy, thereby enhancing its own phase stability. The coupling between order-templated ligation and selectivity provided by supramolecular ordering enables an autocatalytic cycle favouring the growth of DNA chains, up to biologically relevant lengths, from few-base long oligomers. This finding suggests a novel scenario for the abiotic origin of nucleic acids.
据观察，短DNA寡聚物的浓缩溶液由于分层结构的超分子自组装而呈现液晶有序排列。在具有不同互补程度的寡聚物混合物中，液晶微区是通过那些具有足够双链化程度和物理聚合倾向的寡聚物的选择性聚集而形成的。在此我们表明，这些微区充当流体且可渗透的微反应器，其中双链末端之间的有序稳定分子接触作为其化学连接的物理模板。在非生物缩合剂存在的情况下，液晶有序排列显著提高连接效率，从而增强其自身的相稳定性。超分子有序排列提供的有序模板连接与选择性之间的耦合，使得能够形成一个自催化循环，有利于从几碱基长的寡聚物生长出与生物学相关长度的DNA链。这一发现为核酸的非生物起源提出了一种新的设想。
