Factors affecting the efficiency of protein synthesis in Escherichia coli. Production of a polypeptide of more than 6000 amino acid residues.
Factors affecting the efficiency of protein synthesis were analyzed in Escherichia coli. For this purpose the lacZ gene was fused to produce polypeptides from a dimer (molecular weight 229,957) to a hexamer (molecular weight 684,924) of beta-galactosidase. From pulse-chase experiments it was found that only 45% of the ribosomes which reached to the end of the first monomer were able to complete the second monomer unit. Similarly, for every addition of a monomer unit to synthesize the multimers from the trimer to the hexamer approximately half of the ribosomes failed to complete the synthesis of the added unit. Furthermore, the stability of the polypeptides decreased as their sizes increased. As a result, the overall efficiency of the production of the beta-galactosidase polymers dropped by a factor of approximately 3 on a weight basis for each addition of a monomer unit.
Tsung
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K
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635.
Inouye
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Inouye
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D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000096:biosynthesis*; D004262:DNA Restriction Enzymes; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D005696:Galactosidases / Q000096:biosynthesis*; D007163:Immunosorbent Techniques; D007763:Lac Operon; D046911:Macromolecular Substances; D008970:Molecular Weight; D010441:Peptide Chain Elongation, Translational; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D012270:Ribosomes / Q000378:metabolism; D014169:Transformation, Bacterial; D001616:beta-Galactosidase / Q000096:biosynthesis* / Q000235:genetics
D000596:Amino Acids; D001426:Bacterial Proteins; D046911:Macromolecular Substances; D012333:RNA, Messenger; D004262:DNA Restriction Enzymes; D005696:Galactosidases; D001616:beta-Galactosidase