美國(guó)科學(xué)家在《自然》雜志上撰文指出，他們利用噬菌體，在實(shí)驗(yàn)室中讓生物分子的進(jìn)化速度提高了100倍,。新研究有望讓制藥業(yè)使用實(shí)驗(yàn)室培育出來(lái)的蛋白質(zhì),、核酸和其他成分按需制藥,。
噬菌體輔助持續(xù)進(jìn)化（PACE）
該研究的領(lǐng)導(dǎo)者,、哈佛大學(xué)化學(xué)和生化教授戴維·劉說(shuō),，大多數(shù)現(xiàn)代藥物都由有機(jī)小分子制成,，但某些情況下,，蛋白質(zhì)或核酸等生物大分子可能更適合用來(lái)制藥。但這種生物大分子如何快速地制造一直是一大難題,，新研究提供了一種新的解決辦法,。
科學(xué)家表示，雖然生物分子也會(huì)自然進(jìn)化,，但整個(gè)進(jìn)化過(guò)程耗時(shí)很長(zhǎng),，最終結(jié)果也無(wú)法控制。因此,，幾十年來(lái),，科學(xué)家一直使用實(shí)驗(yàn)室進(jìn)化（直接進(jìn)化）來(lái)生產(chǎn)具有特定性能的生物分子，但實(shí)驗(yàn)室進(jìn)化的速率通常為每幾天一輪,，而且,，在此期間，科學(xué)家或技術(shù)人員需要定期對(duì)樣本進(jìn)行操作,。
而戴維·劉和同事研究出來(lái)的最新方法——噬菌體輔助持續(xù)進(jìn)化（PACE）通過(guò)讓生物分子的實(shí)驗(yàn)室進(jìn)化和一種噬菌體的生命周期結(jié)合在一起,，讓蛋白質(zhì)在每24小時(shí)內(nèi)進(jìn)化60輪。
PACE的效率是傳統(tǒng)實(shí)驗(yàn)室進(jìn)化方法的100倍左右,，整個(gè)實(shí)驗(yàn)過(guò)程也無(wú)需人為干預(yù),，大大節(jié)省了科學(xué)家的勞動(dòng)成本。除此之外,，新方法使用的材料也很容易獲得,，另外，也可通過(guò)設(shè)計(jì),，攔住某些不需要的“騙子”分子,。
科學(xué)家表示，該噬菌體的生命周期僅為10分鐘,，是已知噬菌體中生命周期最短的,。PACE系統(tǒng)使用大腸桿菌的宿主細(xì)胞作為制造噬菌體細(xì)胞的工廠，使用噬菌體的基因編碼讓生物分子繁殖,，生成所需要的蛋白質(zhì),。
科學(xué)家在《自然》雜志上寫(xiě)道：“實(shí)驗(yàn)室進(jìn)化已制造出很多具有特定性能的生物分子,，但一輪變異、基因表達(dá),、篩選或選擇,、復(fù)制過(guò)程一般耗時(shí)幾天甚至更長(zhǎng)時(shí)間，而且需要人為干預(yù),。既然進(jìn)化成功與否主要取決于最終進(jìn)化出的輪數(shù),，因此，一種讓實(shí)驗(yàn)室進(jìn)化更快速進(jìn)行的方法能顯著增強(qiáng)其效率,。”（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09929
A system for the continuous directed evolution of biomolecules
Kevin M. Esvelt,1 Jacob C. Carlson2 & David R. Liu2, 3
Laboratory evolution has generated many biomolecules with desired properties, but a single round of mutation, gene expression, screening or selection, and replication typically requires days or longer with frequent human intervention1. Because evolutionary success is dependent on the total number of rounds performed2, a means of performing laboratory evolution continuously and rapidly could dramatically enhance its effectiveness3. Although researchers have accelerated individual steps in the evolutionary cycle4, 5, 6, 7, 8, 9, the only previous example of continuous directed evolution was the landmark study of Wright and Joyce10, who continuously evolved RNA ligase ribozymes with an in vitro replication cycle that unfortunately cannot be easily adapted to other biomolecules. Here we describe a system that enables the continuous directed evolution of gene-encoded molecules that can be linked to protein production in Escherichia coli. During phage-assisted continuous evolution (PACE), evolving genes are transferred from host cell to host cell through a modified bacteriophage life cycle in a manner that is dependent on the activity of interest. Dozens of rounds of evolution can occur in a single day of PACE without human intervention. Using PACE, we evolved T7 RNA polymerase (RNAP) variants that recognize a distinct promoter, initiate transcripts with ATP instead of GTP, and initiate transcripts with CTP. In one example, PACE executed 200 rounds of protein evolution over the course of 8?days. Starting from undetectable activity levels in two of these cases, enzymes with each of the three target activities emerged in less than 1?week of PACE. In all three cases, PACE-evolved polymerase activities exceeded or were comparable to that of the wild-type T7 RNAP on its wild-type promoter, representing improvements of up to several hundred-fold. By greatly accelerating laboratory evolution, PACE may provide solutions to otherwise intractable directed evolution problems and address novel questions about molecular evolution.
