據(jù)每日科學(xué)網(wǎng)站10月18日（北京時(shí)間）報(bào)道,，紐約大學(xué)科學(xué)家研發(fā)出一種能自我復(fù)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(chǔ)。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(fù)制在生物體中普遍存在，但人造結(jié)構(gòu)的自我復(fù)制卻很難實(shí)現(xiàn),。此次研究是邁向自主復(fù)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(fù)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(fù)制了包含復(fù)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(xì)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(duì)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(gè)DNA雙螺旋結(jié)構(gòu)的彎曲三螺旋分子（BTX）。每個(gè)BTX分子由10個(gè)DNA索烴構(gòu)成,，與DNA不同的是,，BTX的編碼不局限于4個(gè)字母，它能夠包含108個(gè)不同字母和模片,，借助4個(gè)DNA單索的互補(bǔ)形成一對(duì),，或在每個(gè)模片上形成“黏性末端”，直至構(gòu)成最終的6個(gè)螺旋束（six-helix bundle）,。
為實(shí)現(xiàn)BTX自我復(fù)制模片陣列，需要“種子”結(jié)構(gòu)促進(jìn)多代相同陣列的形成,。BTX“種子”被放置于化學(xué)溶液中,，由7個(gè)模片組成,，模片可以互補(bǔ)形成子代BTX陣列，該陣列隨后會(huì)在溶液加熱至40℃時(shí)與“種子”分離,，并循環(huán)重復(fù)這一過程,，形成第三代陣列，從而實(shí)現(xiàn)材料的自我復(fù)制及“種子”的信息復(fù)制,。值得注意的是,，這個(gè)過程與發(fā)生在細(xì)胞內(nèi)部的復(fù)制過程不同，因?yàn)閳?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?；瘜W(xué)系的納德里安·西曼指出：“雖然我們的復(fù)制方法需要多種化學(xué)物質(zhì)和加熱過程,，但已經(jīng)證明不僅可以復(fù)制DNA或RNA等細(xì)胞分子,，還可以復(fù)制眾多特別的結(jié)構(gòu),，實(shí)現(xiàn)多個(gè)化學(xué)形態(tài)不同、功能特性相異的結(jié)構(gòu)的復(fù)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.
