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  • 高级翻译 - 高级翻译

    Translation

     

    to . How?
    ::怎么会这样?

    You must translate. To go from one language to another. Spanish to English, French to German, or nucleotides to amino acids . Which type is the translation of molecular biology ? Obviously, the type of translating discussed here translates from the language of nucleotides to the language of amino acids.
    ::您必须翻译。 要从一种语言翻译成另一种语言, 西班牙语到英语, 法语到德语, 核糖酸到氨基酸。 哪一种是分子生物学的翻译? 显然, 这里讨论的翻译类型可以从核糖酸的语言翻译成氨基酸的语言 。

    Translation
    ::笔译 笔译

    Translation is “RNA → protein.” In other words, translation is the transfer of the genetic instructions in RNA to a protein made of amino acids. Translation uses the products of , mRNA, tRNA , and rRNA, to convert the mRNA sequence into a polypeptide according to the . The mRNA moves from the to the cytoplasm to interact with a , which serves as the site of translation. Translation proceeds in three phases: initiation , elongation and termination .
    ::换句话说,翻译是指将RNA的遗传说明转换为氨基酸的蛋白质。翻译使用mRNA、tRNA和RNA的产物,将mRNA序列转换成一种多孔化物。MRNA从圆顶虫移到圆顶虫与一个作为翻译场所的圆顶虫相互作用。翻译分三个阶段进行:启动、延长和终止。

    To understand translation, first we need to understand the ribosome. Ribosomes are composed of two subunits, a small subunit and a larger subunit. Prokaryotic subunits are named the 30S and 50S subunits; eukaryotic subunits are named the 40S and 60S subunits. During translation the tRNA molecules are literally “inside” the ribosomal subunits, as they sit on the mRNA strand. When tRNAs come to the ribosome, adjacent amino acids are brought together, allowing the ribosome to catalyze the formation of the peptide bond between amino acids. The ribosome has three tRNA binding sites: the A site, the P site, and the E site ( Figure  ). The A site binds a tRNA with an attached amino acid. The P site contains the tRNA with the growing polypeptide chain attached, and the E site contains the tRNA that no longer has an attached amino acid. This tRNA is preparing to exit the ribosome. A single mRNA can be translated simultaneously by multiple ribosomes.
    ::为了理解翻译, 首先我们需要理解核糖核酸。 Riboomes 由两个子单位、 一个小子单位和一个更大的子单位组成。 Prokayome 子单位的名称是 30S 和 50S 子单位; eukary 子单位的名称是 40S 和 60S 子单位。 在翻译过程中, tRNA 分子实际上是“ 内部” 的核糖核酸亚单位, 因为它们坐在 mRNA 线上。 当 tRNA 到达核糖核酸, 相邻的氨基酸 聚集在一起, 使核糖核酸 催化氨酸 之间 浸泡酸 联系 的形成 。 核糖核酸 3 tRNA 的连接点是 A 站、 P 站点 和 E 站点 ( Figure ) 。 将核糖核糖核酸连接在一起。 P 站点包含tRNA 和 相连接的聚苯基物质链, 使核糖核糖核酸 不再附着多氨酸。

    lesson content
    This cartoon depicts the relative location of the E, P, and A sites within the ribosome. The A site binds a tRNA bound to an amino acid, the P site binds a tRNA bound to the polypeptide being synthesized, and the E site binds a tRNA without an attached amino acid before the tRNA exits the ribosome.

    Role of tRNA
    ::TRNA的作用

    Transfer RNAs or tRNAs bring or tansfer the proper amino acid to the ribosome based on the genetic code. The anticodon at the bottom of the tRNA molecule binds to the codon on the mRNA. The codon on the mRNA is specific for an amino acid or stop codon . Stop codons do not have corresponding tRNA molecules, and signify the end of translation. The amino acid is attached to the 3' end of the tRNA. Only one amino acid can be attached to a tRNA, based on that tRNA's anticodon. Because there are 61 separate codons (actually 64, but three are stop codons) that can bind to anticodons, there must be 61 different tRNAs in a . The covalent attachment of an amino acid to the tRNA is catalyzed by called aminoacyl-tRNA syntheses through a process called aminoacylation. Aminoacyl tRNA synthetase, through aminoacylation, produces aminoacyl-tRNA molecules with an amino acid attached to their 3- ends. There is a single aminoacyl tRNA synthetase for each amino acid. This process is also known as "charging" the tRNA with the amino acid.
    ::RNAs 或 tRNAs 将适当的氨酸转移至基于遗传代码的血清, 或将适当的氨酸移植到血清中。 tRNA 分子底部的抗codon 与 mRNA 的codon 结合。 mRNA 上的codon 具体针对的是氨酸或停止codon 。 停止 conds 没有相应的tRNA 分子, 并且表示翻译的结束 。 氨酸附于tRNA 的3 端 。 只有一种氨酸可以附于tRNA 的tRNA 。 基于 tRNA 的抗codon 的抗codon 。 因为有61个单独的cods( 事实上是64个, 但三个是停止 codon) , 在一种抗cocodondon 中, 氨酸与tRNA 3Rancial 的氨基 亚麻黄酸三联 进程也通过一个已知的氨酸三氨基进程进行。

    Initiation in Prokaryotes
    ::Prokaryotes的启动

    The initiation of translation in involves the assembly of the ribosome and addition of the first amino acid, methionine. The 30S ribosomal subunit attaches to the mRNA. Next, the specific methionine tRNA is brought into the P. The anticodon of this tRNA will bind to the AUG (start) codon on the mRNA. This is the only time a tRNA will be brought into the P site; all successive tRNA’s will be brought to the A site as translation continues. The 50S ribosomal subunit then binds to the 30S subunit, completing the ribosome.
    ::翻译的启动涉及对乳黄素的组装和添加第一个氨基酸甲基硫素。 30S的血清子单位附属于 mRNA 。 接下来, 特定的甲基硫素 TRNA 引入P 。 这个tRNA 的抗codon 将约束在 mRNA 上的 AUG ( 启动) codon 。 这是将tRNA 引入P 站点的唯一时间; 所有相继的tRNA 将随着翻译的继续被带入 A 站点。 50S 的血清子单位随后连接到 30S 子单位, 完成 ribooms 。

    Initiation in Eukaryotes
    ::Eukaryotes的启动

    The initiation of protein translation in eukaryotes is similar to that of prokaryotes with some minor modifications. The 5' cap and 3' poly(A) tail are involved in the recruitment of the ribosome. In eukaryotes the ribosome scans along the mRNA for the first start methionine codon. Translation may begin at all AUG codons, however only an in-frame AUG will produce a functional polypeptide. The tRNAs with attached amino acids are delivered to the ribosome by proteins called elongation factors (EF-Tu in , eEF-1 in eukaryotes), which aid in decoding the mRNA codon sequence.
    ::eukaryotes 蛋白质转换的启动与 prokaryotes 的启动类似,但稍作修改。 5' 上限和 3' 聚(A) 尾尾尾尾尾是用于招募红蛋白。 在 eukarytes 沿 mRNA 进行血清扫描, 首次启动甲基苯丙胺codon 。 翻译可能从所有 AUG codon 开始, 但是只有 内部 AUG 才能产生功能性聚苯酯。 配有氨基酸的tRNA 由被称为延延因的蛋白(EF-Tu in eukaryotes, eEF-1 in eF-Tu eEF- eF1) 交付给血清组, 帮助解出 mRNA Codon 序列。

    Elongation
    ::长长

    Elongation is fairly similar between prokaryotes and eukaryotes. As translation begins, the start tRNA is sitting on the AUG codon in the P site of the ribosome, so the next codon available to accept a tRNA is at the A site. Elongation proceeds after initiation with the binding of an tRNA to the A site. The next tRNA binds to the codon, bringing the appropriate amino acid to the ribosome, and a peptide bond joins between the start methionine and the next amino acid. This reaction is catalyzed by the ribosome. The new polypeptide chain is released from the initial tRNA. The entire ribosome complex moves along the mRNA, sending the first tRNA into the E site and the tRNA with the growing polypeptide into the P site. The A site is now empty and ready to accept another tRNA. The first tRNA now leaves the ribosome. The A site accepts a tRNA with an attached amino acid, a peptide bond forms between the two adjacent amino acids, and the process continues.
    ::随着翻译的开始,TRNA将进入AUG Codon, 在Riocome P站点的AUG Codon, 所以下一个可以接受tRNA的codon将进入A站点。 在开始将tRNA捆绑到A站点之后, 延长会继续。 下一个tRNA将连接到codon, 将适当的氨酸带入Riocome, 并连接在开始甲基安非他明和下一个氨基酸之间的一种浸渍联结。 第一次tRNA现在由Riocome 催化。 新的聚苯丙胺链从最初的 tRNA 释放。 整个树脂复合体沿 mRNA 移动, 将第一个tRNA 送入E 站点, 和不断增长的聚苯丙胺点连接到P站点。 该站点现在已经空并准备接受另一个tRNA。 第一个tRNA 现在离开RNA 。 第一次tRNA 将离开血清 。 。 新的 新的多位链链从初始 tRNA 和相邻的两表 继续接受一个酸 。

    Termination
    ::解雇

    Termination of translation occurs when the ribosome comes to one of the three stop codons, for which there is no tRNA. At this point, a protein called a release factor binds to the A site. The release factor causes the addition of a molecule to the polypeptide chain, resulting in the release of the completed chain from the tRNA and ribosome. The ribosome, release factor, and tRNAs then dissociate and translation is complete. The process of translation is summarized in Figure  .
    ::翻译的终止发生在三端codon(没有 tRNA ) 中的一种情况下。 此时, 一种被称为释放因子的蛋白质与 A 点相连接。 释放因子导致聚苯二酸酯链中添加分子, 导致从 tRNA 和 riboome 中释放完整的链条。 排卵因子、 释放因子和 tRNA 完成分解和翻译。 翻译过程在图中概述 。

    lesson content
    Summary of translation. Notice the mRNA segment within the ribosome. A tRNA anticodon binds to the appropriate codon, bringing the corresponding amino acid into the ribosome where it can be added to the growing polypeptide chain.

    Post-Translational Modification and Protein Folding
    ::翻译后修改和蛋白质折叠

    The events following often include post-translational modification of the peptide chain and folding of the protein into its functional conformation. During and after synthesis, polypeptide chains often fold into secondary and then tertiary structures. These levels of organization were discussed in the : Proteins (Advanced) concept. Briefly, the primary structure of the protein is the sequence of amino acids determined by the gene and mRNA. The secondary and tertiary structures are determined by interactions between the amino acids within the polypeptide ( Figure ).
    ::以下事件往往包括peptide链的翻译后修改和将蛋白质折叠成其功能一致性。在合成期间和之后,聚石化链往往折叠在二级和三级结构中。这些层次的组织安排在下列概念中讨论:Proteins(高级)概念。蛋白的主要结构是由基因和 mRNA决定的氨酸序列。二级和三级结构由聚石化内氨酸之间的相互作用决定(图)。

    Many proteins undergo post-translational modification, allowing them to then perform their specific function. This may include the formation of disulfide bridges or attachment of any of a number of biochemical functional groups, such as phosphate groups, or . Certain amino acids may be removed, or the polypeptide chain may be cut into two pieces. Lastly, two or more polypeptides may interact with each other, forming a functional protein with a quaternary structure.
    ::许多蛋白质在翻译后经过修改,允许它们随后发挥特定功能,包括形成脱硫桥或若干生化功能组(如磷酸盐组)中任何一组生物化学功能组(如磷酸盐组)的附加物。某些氨基酸可以去除,或将聚苯醚链切成两块。最后,两个或两个以上的聚苯醚可以相互作用,形成一种带有四元结构的功能性蛋白。

    lesson content
    The four stages of protein folding.

    Summary
    ::摘要

    • During translation, a protein is synthesized using the codons in mRNA as a guide.
      ::在翻译过程中,蛋白质会以 mRNA 中的codon 做为指南,合成蛋白质。
    • Translation involves the interactions of the three types of RNA: mRNA, rRNA and tRNA.
      ::翻译涉及三种RNA的相互作用:MRNA、RRNA和tRNA。
    • After the protein is made, it must fold into its functional conformation.
      ::蛋白质制成后,必须折叠成其功能分解。

    Review
    ::回顾

    1. Outline the steps of translation in eukaryotes.
      ::以 eukaryotes 概要描述翻译步骤 。
    2. What are the ribosomes three tRNA binding sites?
      ::三个tRNA装订地点是什么?
    3. How is translation related to the central dogma of molecular biology?
      ::如何翻译与分子生物学的中心教条有关?
    4. What is protein folding?
      ::什么是蛋白质折叠?