Читать книгу Snyder and Champness Molecular Genetics of Bacteria - Tina M. Henkin - Страница 131

1  Overview

2  The Structure and Function of RNA Types of RNA RNA Precursors RNA Structure RNA Processing and Modification

3  Transcription Structure of Bacterial RNA Polymerase Overview of Transcription Details of Transcription rRNAs and tRNAs

4  RNA Degradation RNases

5  The Structure and Function of Proteins Protein Structure

6  Translation Structure of the Bacterial Ribosome Overview of Translation Details of Protein Synthesis The Genetic Code Polycistronic mRNA

7  Protein Folding and Degradation Protein Chaperones Protein Degradation

8  Protein Localization The Translocase System The Signal Sequence The Targeting Factors The Tat Secretion Pathway Disulfide Bonds

9  Protein Secretion and Export Protein Secretion Systems in Bacteria with an Outer Membrane Protein Secretion in Bacteria That Lack an Outer Membrane Sortases

10  Regulation of Gene Expression Transcriptional Regulation Posttranscriptional Regulation

11  What You Need To Know Open Reading Frames Transcriptional and Translational Fusions

12  BOX 2.1 Antibiotic Inhibitors of Transcription

13  BOX 2.2 Molecular Phylogeny

14  BOX 2.3 Antibiotic Inhibitors of Translation

15  BOX 2.4 Mimicry in Translation

16  BOX 2.5 Exceptions to the Code

Fluorescence of transformants expressing MBP-GFP hybrid proteins. MC4100 transformed with the following: 1, pMGP2; 2, pMGC2; 8, MM52 [secA(Ts)] transformed with pMGP2; 3, pMGC2; 7, CK2163 (secB) transformed with pMGP2; 4, pMGC2; 6, IQ85 [secY(Ts)] transformed with pMGP2; and 5, pMGC2. From Feilmeier et al. 2000 (see Suggested Reading).

UNCOVERING THE MECHANISM OF PROTEIN SYNTHESIS, and therefore of gene expression, was one of the most significant accomplishments in the history of science. The process of gene expression is called the central dogma of molecular biology, which states that information stored in DNA is copied into RNA and then translated into protein. We now know of many exceptions to the central dogma. For example, information can sometimes flow in the reverse direction, from RNA to DNA. The information in RNA also can be changed after it has been copied from the DNA. Moreover, the information in DNA may be expressed differently depending on where it is in the genome. Despite these exceptions, however, the basic principles of the central dogma remain sound.

This chapter outlines the process of gene expression and protein synthesis, with a brief discussion of how proteins can be differentially localized after synthesis. The discussion is meant to be only a broad overview, with special emphasis on topics essential to an understanding of the chapters that follow and on subjects unique to bacteria. For more detailed treatments, consult any modern biochemistry textbook.