In Vivo Experimental Evolution: Re-evolving RNase P RNA

9981394 dorit这个项目提出重新进化所有活细胞代谢机制的一个关键组成部分，核糖核蛋白RNaseP。实验进化系统允许在大肠杆菌中发现的自然发生的RNaseP被替换为替代的工程版本。这些合成版本，要么是从相关细菌中存在的RNaseP变体中衍生出来的，要么是在实验室中设计出来的，被放置在质粒载体上，用来取代内源性RNaseP。在体内重复几代的实验选择导致全功能替代品的进化，然后可以将其与自然发生的对应物进行比较和对比。这项研究是首次明确尝试揭示在自然界中未见的重要代谢成分的替代功能版本的存在之一。虽然当代生物中存在的RNaseP版本是数十亿年自然进化的精致结果，但它们可能只是细菌面临的催化挑战的可能解决方案的一小部分。该系统深入研究了这些未被采用的道路，并探索了针对给定催化挑战的现有解决方案的空间。这样，就可以理解偶然性、偶然性和选择所起的相对作用。该系统还提供了一种通用工具，用于探测代谢机制的任何组成部分的功能灵活性，以及测试天然存在的蛋白质和核酸的工程替代品的性能的方法。

9981394DoritThis project proposes to re-evolve a critical component of the metabolic machinery of all living cells, the ribonucleoprotein RNaseP. The experimental evolution system that permits replacement of the naturally occurring RNaseP found in the E. coli bacterium with alternate, engineered versions. These synthetic versions, derived either from the variants of RNaseP present in related bacteria, or designed in the laboratory, are placed on a plasmid vector and used to displace the endogenous RNaseP. Repeated generations of in vivo experimental selection result in the evolution of fully functional alternatives that can then be compared and contrasted to their naturally occurring counterparts.This study is one of the first explicit attempts to uncover the existence of alternate functional versions of important metabolic components that are not seen in the natural world. While the versions of RNaseP present in contemporary organism are the exquisite result of billions of years of natural evolution, they likely represent but a small subset of possible solutions to the catalytic challenges facing bacteria. This system delves into these roads not taken, and explores the space separating existing solutions to a given catalytic challenge. In so doing, the relative roles played by contingency, chance, and selection can be understood. This system also provides a general tool with which to probe the functional flexibility of any component of the metabolic machinery, as well as a method for testing the performance of engineered alternatives to naturally occurring proteins and nucleic acids.H:\popbio\abstracts\fy2000\9981394 (Dorit abstract)