Protein Translation Overview

Translation converts the genetic information embodied in the base sequence (codon) of mRNA into the amino acid sequence of a polypeptide chain on ribosomes. Protein biosynthesis (Amstein and Cox, 1992 Lee and Lorsch, 2(X)4 Moldave, 1981) begins with the activated amino acids (aminoacyl-tRNA) and is characterized by three distinct phases initiation, elongation and termination. 

1 Synthesis of aminoacyl-tRNA. Amino acids are activated to 3 -0-aminoacyl-tRNAs (aa-tRNAs), which are delivered to ribosomes to form peptide bonds. The activation of amino acids is catalyzed by 20 different aminoacyl-tRNA synthetases (aRS s), each catalyzes the ATP-dependent esterification of its specific amino acid to the cognate tRNA (Amez and Moras, 1997). Thus aRS reaction serves to  

activate the amino acid so that it may react to form a peptide bond and 

bridge the information gap (or difference) between amino acids and nucleotides (codons). 

activation of the amino acid via ATP-dependent formation of an aminoacyl adenylate and 

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There are two steps in protein synthesis where polarity of information is important. The first is the relationship between the 50 to 30 directionality of mRNA, and the NH3+ to COO- terminal direction of protein synthesis. The utilization of tRNA as the adaptor is the second step where polarity of information is crucial. The tRNA has a bipolar function, it needs to correctly link each amino acid to the corresponding position encoded by the mRNA. Figure 26.1 shows an overview of how mRNA synthesis and protein translation share the same polarity. Moreover, similar to transcription, translation can also be broken down into three discrete components initiation, elongation, and termination. 

See also Translation Overview (from Chapter 27), Proteins... 

Proteomics is an interdisciplinary science that includes biology, bioinformatics, and protein chemistry. The purpose of this book is to provide the reader with an overview of the types of questions being addressed in proteomics studies and the technologies used to address those questions. The first chapter is a concise outline of the field as it presently stands. The second chapter provides an overview of the use of 2D-gel electrophoresis and mass spectrometry to identify proteins, as well as post-translational... 

Figure 14.13 Overview of the concept of the antisense approach the end goal is the prevention of expression of a particular gene product (invariably a protein) by either blocking the transcription or translation of that gene...

Figure 1 Overview of specific use of seienium in bioiogical systems. Selenium can be incorporated into macromolecules in at least three separate pathways. From the reduced form of selenide, selenium is activated to selenophosphate by the action of the enzyme selenophosphate synthetase (SPS or SelD). This activated form is then used as a substrate for pathway-specific enzymes that lead to (1) insertion as selenocysteine into proteins during translation (selenoproteins), (2) incorporation into tRNA molecules as mnm Se U or Se U, and (3) insertion into a unique class of molybdoenzymes as a labile, but required, cofactor. The need for activation to selenophosphate has been demonstrated in all cases at the genetic and biochemical level, with the exception of the labile selenoenzymes, where activation of selenium has only been proposed based on proximity of genes within an operon encoding SPS and a molybdoenzyme. ...

We begin by examining the interactions between proteins and DNA that are the key to transcriptional regulation. We next discuss the specific proteins that influence the expression of specific genes, first in prokaryotic and then in eukaryotic cells. Information about posttranscriptional and translational regulation is included in the discussion, where relevant, to provide a more complete overview of the rich complexity of regulatory mechanisms. 

An overview of protein synthesis is shown in Fig. S.A12. The linear sequence in mRNA that is translated to protein contains four bases, adenine, uracil, guanine and cytosine. The four letters A,U,G and C constitute the mRNA alphabet . This basic alphabet is used in triplets of bases called codons. The codons on mRNA pair up with anticodon or complementary triplets on the tRNA, thus matching the mRNA code to an amino-acid sequence. 

Fig. 1. Overview of the wheat germ cell-free translation system developed at our laboratory. The sequential establishment of the system started with stabilization, followed by integration with flexible plasmid of Ehime University (pEU) vector and finally high-throughput protein synthesis. (From ref. 21a, with permission from Elsevier.)...

Expanding the Genetic Code Through Chemical Biology Protein Syndiesis, Key Reactions of Protein-Nucleic Acid Interactions Translation An Overview... 

Fig 12.7 Overview of Protein biosynthesis and Post translational modifications. Translational Inhibitors Antibiotics... 

An overview of protein synthesis is illustrated in Figure 19.3. Despite its complexity and the variations among species, the translation of a genetic message into the primary sequence of a polypeptide can be divided into three phases initiation,... 

The critical role that protein factors play in translation is discussed next, including initiation, elongation, and release factors. The termination of translation is outlined, and the role of release factors that recognize translation stop codons is described. The chapter closes with a brief overview of translation in eukaryotes, emphasizing the major contrasting features with respect to translation in prokaryotes. Differences in the initiator tRNA, the selection mechanism of the initiator codon, the ribosomes, and the overall complexity of the process are highlighted. Last, the mechanisms of several potent inhibitors of translation and the mechanism of the bacterial toxin that causes diphtheria is presented. 

FIGURE 6.3 An overview of gene expression. A gene is typically regulated by an upstream promoter through the action of transcription factors, resulting in the synthesis of an mRNA from the DNA template in a process known as transcription. This mRNA will later on get translated into a protein through the action of ribosomes. 

Walsh, G. Post-translational modifications in the context of therapeutic proteins An introductory overview. In Post-translational Modification of Protein Biopharmaceuticals, (G. Walsh, ed.), Wiley-VCH, Weinhaim, pp. 1-76, 2009. 

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