Novel nucleic acids nanobiotechnology integrated with materials science

1. 我们一直对DNA与阳离子梳型共聚物聚（l -赖氨酸）-接枝-葡聚糖（PLL-g-Dex）之间的可溶性多电解质复合物（IPEC）感兴趣，该复合物由一个聚赖氨酸主链和大量的葡聚糖亲水接枝链组成，可作为核酸结合蛋白的模型。共聚物形成一种完全可溶的IPEC，其中DNA线圈-球结构转变，即压实，被抑制。该复合物的可溶性性质使我们能够从光谱上监测高碱性聚合物对DNA杂交的影响。我们发现，在生理相关条件下，静电等量的梳子型共聚物增加了双链DNA和三链DNA的稳定性。此外，我们发现共聚物刺激了DNA与互补的单链DNA之间的链交换反应，并且e…More表现出核酸伴游活性。核酸杂交是基因在体内表达、复制和重组的关键过程。然而，对于生物技术而言，即使在低DNA浓度下杂交率的提高也尤为重要。在生理相关的离子条件下，纳米摩尔浓度的聚l -赖氨酸接枝葡聚糖可显著提高dna杂交率200倍以上。为了更好地应用和发展DNA纳米机器，需要改进其响应动力学、输出和序列选择性。此外，DNA纳米机器目前在操作条件上有一些限制。在这项研究中，我们证明了聚（l -赖氨酸）-接枝-葡聚糖在中等条件下，包括生理相关条件下，即使在非常低的链浓度（纳摩尔/升范围）下，通过混合稳定和DNA链交换加速，也能产生强大而快速的DNA纳米机器反应。少

1. Water soluble polyelectrolyte complex between cationic comb-type copolymer and nucleic acid We have been interested in the soluble interpolyelectrolyte complexes(IPEC)between DNA and the cationic comb-type copolymers, poly(L-lysine)-graft-dextran(PLL-g-Dex), consisting of a polylysine backbone and abundant hydrophilic graft chains of dextran as a model of nucleic acid-binding proteins. The copolymer forms a totally soluble IPEC in which the DNA coil-globule structural transition, i.e. compaction, is suppressed. The soluble nature of the complex enables us to spectroscopically monitor the effect of highly basic polymers on DNA hybridization. We found that an electrostatically equivalent amount of the comb-type copolymers increased stability of a double-stranded (ds)DNA and a triple-stranded DNA under physiological relevant conditions. Furthermore, we found that the copolymers stimulated the strand-exchange reaction between a ds DNA and its complementary single-stranded (ss)DNA, and e … More xhibit nucleic acid chaperoning activity.2. Acceleration of DNA hybridization by cationic comb-type copolymer Nucleic acid hybridization is a pivotal process in gene expression, replication and recombination in vivo. For biotechnology purposes, however, an increase in hybridization rate even at low DNA concentration is particularly important. Poly(L-lysine)-graft-dextran at nanomolar concentration significantly accelerated DNA-hybridization rate over 200-fold under physiologically relevant ionic conditions.3. Cationic comb-type copolymers for boosting DNA-fueled nanomachines For the better applications and developments of DNA nanomachines, their responding kinetics, output, and sequence-selectivity need to be improved. Furthermore, the DNA nanomachines currently have several limitations in operating conditions. In this study, we showed that poly(L-lysine)-graft-dextran produces the robust and quick responses of DNA nanomachines under moderate conditions including physiologically relevant conditions even at very low strand concentrations(nanomoles per liter range)through hybrid stabilization and DNA strand exchange acceleration. Less