Effects of mutations in heat-shock genes groES and groEL on protein export in Escherichia coli.
Escherichia coli heat-shock proteins GroES and GroEL are essential cytoplasmic proteins, which have been termed 'chaperonins' because of their ability to assist protein assembly of bacteriophage capsids and multimeric enzymes of foreign origin. In this report we show that temperature-sensitive mutations in groES and groEL genes cause defective export of the plasmid-encoded beta-lactamase (Bla) in vivo. Since efficient translocation of proteins across biological membranes is thought to be supported by cytoplasmic factors that protect presecretory molecules from being misfolded, these results suggest that both GroES and GroEL proteins possess a chaperone function by which they facilitate export of Bla. The translocation of other secretory proteins, however, appears to depend minimally on GroE, suggesting that GroE interacts only with a specific class of secreted proteins.
Kusukawa
N
N
Institute for Virus Research, Kyoto University, Japan.
Yura
T
T
Ueguchi
C
C
Akiyama
Y
Y
Ito
K
K
D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001692:Biological Transport; D002458:Cell Fractionation; D018835:Chaperonin 10; D018834:Chaperonin 60; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D011498:Protein Precursors / Q000378:metabolism; D013696:Temperature; D001618:beta-Lactamases / Q000378:metabolism
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D006360:Heat-Shock Proteins; D011498:Protein Precursors; D001618:beta-Lactamases