The Mechanism of Protein Synthesis

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  • 40.1 Protein Synthesis Decodes the Information in Messenger RNA

  • 40.2 Peptidyl Transferase Catalyzes Peptide-Bond Synthesis

  • 40.3 Bacteria and Eukaryotes Differ in the Initiation of Protein Synthesis

  • 40.4 A Variety of Biomolecules Can Inhibit Protein Synthesis

  • 40.5 Ribosomes Bound to the Endoplasmic Reticulum Manufacture Secretory and Membrane Proteins

  • 40.6 Protein Synthesis Is Regulated by a Number of Mechanisms

Henry Ford developed the assembly-line approach to manufacturing in the early 1900s. The assembly line allows the rapid and precise production of many items, including automobiles. Living systems have used this approach for billions of years for protein synthesis, where even very long polypeptide chains can be assembled rapidly and with impressive accuracy.

The synthesis of proteins is an energetically expensive, complicated process consisting of three parts: initiation, elongation, and termination. In initiation, the translation machinery must locate the correct Start codon. In elongation, the codons are read sequentially in the 5′-to-3′ direction as the protein is synthesized from the amino end to the carboxyl end. When a termination codon is reached, special proteins hydrolyze the polypeptide from the last transfer RNA, releasing the completed protein. The translation machinery comes apart and is ready to begin another round of protein synthesis.

We begin our consideration of protein synthesis by examining this process in bacteria. We then compare protein synthesis in bacteria and in eukaryotes. Finally, we consider how protein synthesis is affected by environmental factors, such as inhibitors and cell structure, and how the process is regulated.

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