title: Folding in vivo of bacterial cytoplasmic proteins: role of GroEL.
abstract: A general role for chaperonin ring structures in mediating folding of newly translated proteins has been suggested. Here we have directly examined the role of the E. coli chaperonin GroEL in the bacterial cytoplasm by production of temperature-sensitive lethal mutations in this essential gene. After shift to nonpermissive temperature, the rate of general translation in the mutant cells was reduced, but, more specifically, a defined group of cytoplasmic proteins--including citrate synthase, ketoglutarate dehydrogenase, and polynucleotide phosphorylase--were translated but failed to reach native form. Similarly, a monomeric test protein, maltose-binding protein, devoid of its signal domain, was translated but failed to fold to its native conformation. We conclude that GroEL indeed is a machine at the distal end of the pathway of transfer of genetic information, assisting a large and specific set of newly translated cytoplasmic proteins to reach their native tertiary structures.
authors.affiliation: Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510.
authors.forename: A L
authors.initials: AL
authors.lastname: Horwich
authors.forename: K B
authors.initials: KB
authors.lastname: Low
authors.forename: W A
authors.initials: WA
authors.lastname: Fenton
authors.forename: I N
authors.initials: IN
authors.lastname: Hirshfield
authors.forename: K
authors.initials: K
authors.lastname: Furtak
mesh_terms: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D010582:Bacteriophage lambda / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D018834:Chaperonin 60; D002950:Citrate (si)-Synthase / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D007655:Ketoglutarate Dehydrogenase Complex / Q000096:biosynthesis; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D008715:Methionine; D009004:Monosaccharide Transport Proteins; D009876:Operon; D009954:Ornithine Carbamoyltransferase / Q000096:biosynthesis* / Q000235:genetics; D010957:Plasmids; D011117:Polyribonucleotide Nucleotidyltransferase / Q000096:biosynthesis; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D017510:Protein Folding; D021382:Protein Sorting Signals / Q000378:metabolism; D017384:Sequence Deletion; D013696:Temperature; D014161:Transduction, Genetic
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D021382:Protein Sorting Signals; C461599:maltose transport system, E coli; D008320:Maltose; D008715:Methionine; D007655:Ketoglutarate Dehydrogenase Complex; D009954:Ornithine Carbamoyltransferase; D002950:Citrate (si)-Synthase; D011117:Polyribonucleotide Nucleotidyltransferase