據(jù)每日科學網(wǎng)站10月18日（北京時間）報道，紐約大學科學家研發(fā)出一種能自我復制的人造DNA（脫氧核糖核酸）結(jié)構(gòu),，有望為新型材料的制造奠定基礎,。相關(guān)論文發(fā)表在最新一期的《自然》雜志上,。
自然界中,，自我復制在生物體中普遍存在，但人造結(jié)構(gòu)的自我復制卻很難實現(xiàn),。此次研究是邁向自主復制任意類型“種子”結(jié)構(gòu)過程的第一步,。這些“種子”由DNA模片制成，可像字母般組合拼出特定“單詞”,。復制過程保留了模片序列及“種子”形狀,，從而提供了生成下一代結(jié)構(gòu)所需的信息。
此次研究的突破在于成功復制了包含復雜信息的DNA系統(tǒng),。研究人員首先從人造DNA模片開始,，這是DNA的細小排列。DNA的腺嘌呤（A）和胸腺嘧啶（T）,、鳥嘌呤（G）和胞嘧啶(C)互相結(jié)對形成人們熟悉的雙螺旋結(jié)構(gòu),。研究人員制成了含有3個DNA雙螺旋結(jié)構(gòu)的彎曲三螺旋分子（BTX）。每個BTX分子由10個DNA索烴構(gòu)成,，與DNA不同的是,，BTX的編碼不局限于4個字母，它能夠包含108個不同字母和模片,，借助4個DNA單索的互補形成一對,，或在每個模片上形成“黏性末端”，直至構(gòu)成最終的6個螺旋束（six-helix bundle）,。
為實現(xiàn)BTX自我復制模片陣列,，需要“種子”結(jié)構(gòu)促進多代相同陣列的形成。BTX“種子”被放置于化學溶液中,，由7個模片組成,，模片可以互補形成子代BTX陣列，該陣列隨后會在溶液加熱至40℃時與“種子”分離,，并循環(huán)重復這一過程,，形成第三代陣列，從而實現(xiàn)材料的自我復制及“種子”的信息復制,。值得注意的是,，這個過程與發(fā)生在細胞內(nèi)部的復制過程不同，因為執(zhí)行中無需添加酶等生物成分,，即使是DNA模片也由人工合成,。
研究的共同作者,、該校化學系的納德里安·西曼指出：“雖然我們的復制方法需要多種化學物質(zhì)和加熱過程,，但已經(jīng)證明不僅可以復制DNA或RNA等細胞分子,，還可以復制眾多特別的結(jié)構(gòu)，實現(xiàn)多個化學形態(tài)不同,、功能特性相異的結(jié)構(gòu)的復制。”（生物谷 Bioon.com）
doi:10.1038/nature10500
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Self-replication of information-bearing nanoscale patterns
Tong Wang; Ruojie Sha; Rémi Dreyfus; Mirjam E. Leunissen; Corinna Maass; David J. Pine; Paul M. Chaikin; Nadrian C. Seeman
DNA molecules provide what is probably the most iconic example of self-replication—the ability of a system to replicate, or make copies of, itself. In living cells the process is mediated by enzymes and occurs autonomously, with the number of replicas increasing exponentially over time without the need for external manipulation. Self-replication has also been implemented with synthetic systems, including RNA enzymes designed to undergo self-sustained exponential amplification1, 2, 3, 4, 5. An exciting next step would be to use self-replication in materials fabrication, which requires robust and general systems capable of copying and amplifying functional materials or structures. Here we report a first development in this direction, using DNA tile motifs that can recognize and bind complementary tiles in a pre-programmed fashion. We first design tile motifs so they form a seven-tile seed sequence; then use the seeds to instruct the formation of a first generation of complementary seven-tile daughter sequences; and finally use the daughters to instruct the formation of seven-tile granddaughter sequences that are identical to the initial seed sequences. Considering that DNA is a functional material that can organize itself and other molecules into useful structures6, 7, 8, 9, 10, 11, 12, 13, our findings raise the tantalizing prospect that we may one day be able to realize self-replicating materials with various patterns or useful functions.
