Molecular genetics of translational accuracy

核糖体上的蛋白质合成过程是最古老的生物学机制之一， 核糖体可能在第一个细胞之前的RNA世界中进化， 结构，在生命的所有领域中保存的基本部分，了解生物体的机制， 核糖体忠实地将mRNA翻译成蛋白质变得更加重要，也更加容易处理 由于细菌核糖体的两个亚基具有多种分子结构， 配体， 我们的实验室多年来一直对mRNA序列如何 与核糖体相互作用引起程序性错误，我们主要研究了 程序性翻译移码，其中mRNA中的特定位点刺激翻译错误 在速率几个数量级大于随机位置的mRNA，我们的工作和 另一些研究表明，程序化的移码位点操纵核糖体的解码中心， 加剧错误。 最近，我们开始研究错义错误的机制，我们的研究表明， 误差根据误感误差的类型（第一、第二或摆动位置误配对）而变化很大， 根据参与解码密码子的tRNA同种受体，该密码子是错误的位点。主要 我们的工作的结论是，摆动误差普遍存在，但它们不是普遍的， 当竞争的同源tRNA供应不足而不能排除 通过错误的tRNA解码，我们建议进一步表征错义错误的现象学 通过创建一组基于大肠杆菌lacZ和萤火虫荧光素酶的错误报告基因构建体， 基因. Venki Ramakrishnan提出，精确机制的一个主要部分需要 破坏核糖体蛋白S4（rpS 4）和rpS 5之间的蛋白质相互作用， 核糖体转变为“封闭”构象，将氨酰-tRNA捕获在A位点， 该模型基于靶向界面的突变体的存在，所述突变体是 我们的初步数据与此不一致 假设，我们建议通过识别改变准确性的新突变来进一步测试假设， 无论是在rRNA还是核糖体蛋白中， 核糖体上的蛋白质合成过程是 在最古老的生物机制中， 可能是在RNA世界中进化的， 第一个细胞，核糖体已经进化出一个复杂的 结构，在所有结构域中保守的基本部分 了解生命的机制， 核糖体忠实地将mRNA翻译成蛋白质 变得更加重要，也更加容易处理 随着多种分子结构的可用性 细菌核糖体的两个亚基， 配体， 多年来，我们的实验室一直致力于 mRNA序列如何 与核糖体相互作用， 错误，我们主要研究的机制， 程序化翻译移码， mRNA中的特定位点刺激翻译 错误 其速率比 mRNA中的随机位置，我们的工作和 另一些人则发现程序化移码位点 操纵核糖体的解码中心， 加剧错误。 最近，我们开始研究 我们的研究表明， 不同类型的错误 （第一、第二或摆动位置错配）和 根据参与的tRNA同功受体， 解码错误位点的密码子。的 我们工作的结论是，摆动误差 通常发生，但它们并不普遍， 的 其他类型的错误发生时，竞争

The process of protein synthesis on the ribosome is among the oldest of biological mechanisms, having evolved probably in the RNA world before the first cells, The ribosome has evolved an elaborate structure, the essential parts conserved in all domains of life, Understanding the mechanism by which the ribosome faithfully translates mRNAs into proteins has become both more important and more tractable with the availability of multiple molecular structures of both subunits of bacterial ribosomes with various ligands, Our laboratory for many years has been interested in the problem of how mRNA sequences interact with the ribosome to cause programmed errors, We have mainly studied the mechanism of programmed translational frameshifting in which particular sites in mRNAs stimulate translational errors at rates several orders of magnitude greater than at random positions in mRNAs, Our work and that of others revealed that programmed frameshift sites manipulate the decoding center of the ribosome to exacerbate errors. More recently, we have begun to study the mechanism of missense errors, Our study has shown that errors vary widely by type of missense error (first, second or wobble position mispairing) and according to the tRNA isoacceptors involved in decoding the codon that is the site of the error. The major conclusion of our work is that wobble errors commonly occur, tllOugh they are not universal, and that other types of errors occur when the competing cognate tRNA is in insufficient supply to preclude decoding by the errant tRNA, We propose to further characterize the phenomenology of missense errors by creating a set of error-reporter constructs based on the E, coli lacZ and the Photinus (firefly) luciferase genes. Venki Ramakrishnan has proposed that a major part of the accuracy mechanism requiring the disruption ofa protein.protein interaction between ribosomal proteins S4 (rpS4) and rpS5, which allows the ribosome to shift into a "closed" conformation that traps the aminoacyl-tRNA in the A site and allows exit of EF-l A.GDP, The model is based on the existence of mutants targeting the interface that are proposed to destabilize it and cause increased errors, Our preliminary data are inconsistent with this hypothesis, We propose to further test the hypothesis by identifying novel mutations that alter accuracy, either in the rRNA or ribosomal proteins, The process of protein synthesis on the ribosome is among the oldest of biological mechanisms, having evolved probably in the RNA world before the first cells, The ribosome has evolved an elaborate structure, the essential parts conserved in all domains of life, Understanding the mechanism by which the ribosome faithfully translates mRNAs into proteins has become both more important and more tractable with the availability of multiple molecular structures of both subunits of bacterial ribosomes with various ligands, Our laboratory for many years has been interested in the problem of how mRNA sequences interact with the ribosome to cause programmed errors, We have mainly studied the mechanism of programmed translational frameshifting in which particular sites in mRNAs stimulate translational errors at rates several orders of magnitude greater than at random positions in mRNAs, Our work and that of others revealed that programmed frameshift sites manipulate the decoding center of the ribosome to exacerbate errors. More recently, we have begun to study the mechanism of missense errors, Our study has shown that errors vary widely by type of missense error (first, second or wobble position mispairing) and according to the tRNA isoacceptors involved in decoding the codon that is the site of the error. The conclusion of our work is that wobble errors commonly occur, tllOugh they are not universal, and that other types of errors occur when the competing