Topoisomerase activity during the heat shock response in Escherichia coli K-12.
During the upshift of temperature from 30 to 42, 45, 47, or 50 degrees C, an increase in the level of supercoiling of a reporter plasmid was observed. This increase was present in groE and dnaK mutants but was inhibited in cells treated with chloramphenicol and novobiocin. The intracellular [ATP]/[ADP] ratio increased rapidly after an upshift in temperature from 30 to 47 degrees C and then decreased to reach a level above that observed at 30 degrees C. These results suggest that gyrase and proteins synthesized during heat shock are responsible for the changes seen in plasmid supercoiling. Proteins GroE and DnaK are probably not involved in this phenomenon.
Camacho-Carranza
R
R
Departamento de Biología Molecular, Universidad Nacional Autónoma de México, México, D.F.
Membrillo-Hernández
J
J
Ramírez-Santos
J
J
Castro-Dorantes
J
J
Chagoya de Sánchez
V
V
Gómez-Eichelmann
M C
MC
D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D006358:Hot Temperature; D010957:Plasmids / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D011500:Protein Synthesis Inhibitors; D004264:DNA Topoisomerases, Type I; D004250:DNA Topoisomerases, Type II