scholarly journals Inhibition of Escherichia coli DNA topoisomerase I activity by phospholipids

1992 ◽  
Vol 285 (2) ◽  
pp. 503-506 ◽  
Author(s):  
T Mizushima ◽  
S Natori ◽  
K Sekimizu
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Topoisomerase I ◽  
Saturated Fatty Acids ◽  
Egg Yolk ◽  
Inhibitory Effect ◽  
Dna Topoisomerase I ◽  
Dna Topoisomerase ◽  
E Coli ◽  
Dna Relaxation

The DNA relaxation activity of Escherichia coli DNA topoisomerase I in vitro was greatly inhibited by cardiolipin. Inhibition also occurred to some extent with phosphatidylglycerol from egg yolk. Analysis with synthetic phospholipid revealed that phosphatidylglycerol containing unsaturated fatty acids exhibited a strong inhibitory effect, whereas inhibition by phosphatidylglycerol containing saturated fatty acids was weak. Phosphatidylethanolamine showed no inhibitory effect. Chlorpromazine, which interacts with phospholipids, suppressed the inhibitory effect of cardiolipin. Cardiolipin and phosphatidylglycerol with unsaturated fatty acid precipitated topoisomerase I even at low concentrations, whereas phosphatidylglycerol from egg yolk and a synthetic phosphatidylglycerol containing saturated fatty acids precipitated this enzyme only at high concentrations. One-third of the total topoisomerase I in E. coli was found in the membrane fraction. Treatment of E. coli cells with chlorpromazine resulted in relaxation of plasmid DNA. This DNA relaxation was not observed in a topA mutant, suggesting that this relaxation by chlorpromazine in vivo is catalysed by topoisomerase I.

scholarly journals Escherichia coli DNA Topoisomerase I Copurifies with Tn5 Transposase, and Tn5 Transposase Inhibits Topoisomerase I

1999 ◽  
Vol 181 (10) ◽  
pp. 3185-3192 ◽  
Author(s):  
Hesna Yigit ◽  
William S. Reznikoff
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Topoisomerase I ◽  
Dna Topoisomerase ◽  
E Coli ◽  
Dna Relaxation ◽  
Tn5 Transposase ◽  
Derivatives Of

ABSTRACT Tn5 transposase (Tnp) overproduction is lethal toEscherichia coli. Genetic evidence suggested that this killing involves titration of E. coli topoisomerase I (Topo I). Here, we present biochemical evidence that supports this model. Tn5 Tnp copurifies with Topo I while nonkilling derivatives of Tnp, Δ37Tnp and Δ55Tnp (Inhibitor [Inh]), show reduced affinity or no affinity, respectively, for Topo I. In agreement with these results, the presence of Tnp, but not Δ37 or Inh derivatives of Tnp, inhibits the DNA relaxation activity of Topo I in vivo as well as in vitro. Other proteins, including RNA polymerase, are also found to copurify with Tnp. For RNA polymerase, reduced copurification with Tnp is observed in extracts from a topA mutant strain, suggesting that RNA polymerase interacts with Topo I and not Tnp.

scholarly journals Increased Sensitivity to Oxidative Challenges Associated with topA Deletion in Escherichia coli

2000 ◽  
Vol 182 (3) ◽  
pp. 829-832 ◽  
Author(s):  
Yuk-Ching Tse-Dinh
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Topoisomerase I ◽  
Dna Topoisomerase I ◽  
Dna Topoisomerase ◽  
E Coli ◽  
Oxidative Challenge ◽  
Increased Sensitivity ◽  
Negative Supercoiling

ABSTRACT Deletion of topA in Escherichia coli was found to result in a higher level of killing after treatment with either hydrogen peroxide or N-ethylmaleimide. This effect on oxidative challenge response represents a new role for E. coli DNA topoisomerase I in addition to prevention of excessive negative supercoiling of DNA.

ISOLATION OF AN E. COLI DNA TOPOISOMERASE I MUTANT

1980 ◽  
pp. 833-837 ◽  
Author(s):  
Rolf Sternglanz ◽  
Stephen DiNardo ◽  
James C. Wang ◽  
Y. Nishimura ◽  
Y. Hirota
Keyword(s):  
Topoisomerase I ◽  
Dna Topoisomerase I ◽  
Dna Topoisomerase ◽  
E Coli
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