Open AccessTemperature shift‐up leads to simultaneous and continuous plasmid DNA relaxation and induction of DnaK and GroEL proteins in anaerobically growing Escherichia coli cells
Author(s) -
Mizushima Tohru,
Ohtsuka Yoshihisa,
Miki Takeyoshi,
Sekimizu Kazuhisa
Publication year - 1994
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1994.tb07122.x
Subject(s) - groel , heat shock protein , plasmid , escherichia coli , dna , heat shock , shock (circulatory) , biology , groes , hsp70 , microbiology and biotechnology , biochemistry , biophysics , chemistry , gene , medicine
We previously reported that plasmid DNA in Escherichia coli cells growing under aerobic conditions relaxed immediately and transiently after heat shock (Mizushima, T., Natori, S. and Sekimizu, K., Mol. Gen. Genet. (1993) 238, 1–5). We next examined DNA relaxation and induction of heat shock proteins after heat shock in cells growing under anaerobic conditions. DNA in these cells relaxed rapidly (2 min) after heat shock (42°C), as was the case with aerobically growing cells, but full superhelicity was not recovered. The relaxed state of DNA topology was maintained for 60 min after heat shock. Induction of DnaK and GroEL proteins, which was transient in aerobically growing cells, was continuous in anaerobically growing cells. Therefore, induction of heat shock proteins correlated with DNA relaxation in both aerobic and anaerobic conditions.