Origin and Evolution of the Ribosome
Origin and Evolution of the Ribosome
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DOI：
10.1101/cshperspect.a003483
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发表时间：
2010-09-01
影响因子：
7.2
通讯作者：
Fox, George E.
中科院分区：
文献类型：
--
作者：
Fox, George E.
现代核糖体主要是在最后一个共同祖先卢卡的时候形成的。因此，它最早的起源很可能是在RNA世界。其发展的中心是产生现代tRNA的RNA和大核糖体RNA(RRNA)中的一个对称区域，在那里发生肽基转移酶反应。为了理解卢卡之前的发展，有人认为，如果一个人可以推断出它们发生的可能顺序，那么时间上耦合的事件特别有用。利用这样的计时事件，可以推断出大rRNA中各种蛋白质和个别区域的相对年龄。对现代核糖体性质的研究有力地表明，原始核糖体产生的初始多肽可能富含L氨基酸，但并不完全排除D-氨基酸。这对由第一批核糖体制造的多肽的性质有一定的影响。从核糖体起源的角度来看，关于编码的直接问题是它是什么时候出现的，而不是指配是如何进化的。现代核糖体是非常动态的，tRNA进进出出，mRNA相对于核糖体移动。这些移动可能是由于增加了一个模板来保持tRNA而成为可能的。该模板随后将成为信使核糖核酸，从而允许密码的进化，并使RNA基因组变得有用。最后，提出了核糖体历史上主要事件的高度推测的时间线，并讨论了可能的未来方向。
The modern ribosome was largely formed at the time of the last common ancestor, LUCA. Hence its earliest origins likely lie in the RNA world. Central to its development were RNAs that spawned the modern tRNAs and a symmetrical region deep within the large ribosomal RNA, (rRNA), where the peptidyl transferase reaction occurs. To understand pre-LUCA developments, it is argued that events that are coupled in time are especially useful if one can infer a likely order in which they occurred. Using such timing events, the relative age of various proteins and individual regions within the large rRNA are inferred. An examination of the properties of modern ribosomes strongly suggests that the initial peptides made by the primitive ribosomes were likely enriched for L-amino acids, but did not completely exclude D-amino acids. This has implications for the nature of peptides made by the first ribosomes. From the perspective of ribosome origins, the immediate question regarding coding is when did it arise rather than how did the assignments evolve. The modern ribosome is very dynamic with tRNAs moving in and out and the mRNA moving relative to the ribosome. These movements may have become possible as a result of the addition of a template to hold the tRNAs. That template would subsequently become the mRNA, thereby allowing the evolution of the code and making an RNA genome useful. Finally, a highly speculative timeline of major events in ribosome history is presented and possible future directions discussed.