ISSN:
1573-4919
Keywords:
DNA supercoiling
;
DNA topoisomerases
;
[ATP]/[ADP] ratio
;
aerobic anaerobic transitions
;
Escherichia coli
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract This study uncovers a new mechanism of regulation of DNA supercoiling operativein vivo upon an aerobic-anaerobic transition inEscherichia coli. Exponentially growing aerobic batch cultures were subjected to a shift to anaerobic conditions. The ratio [ATP]/[ADP] remained essentially constant at 8.5 in the aerobic culture and after a transition to anaerobiosis while DNA supercoiling increased noticeably upon anaerobiosis. This result indicated that the mechanism of regulation of DNA supercoiling by the [ATP]/[ADP] ratio was not operative. The increase in DNA supercoiling was followed by a large decrease in the DNA-relaxing activity of topoisomerase I while gyrase activity remained relatively constant. This decrease in the activity of topoisomerase I is likely to be responsible for the increase in DNA supercoiling.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00925689
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