FEBS Letters | |
Fast abortive initiation of uvrA promoter in a supercoiled plasmid studied by stopped‐flow techniques | |
Pouyet, J.1  Lefèvre, J.F.1  Daune, M.1  Ling, C.1  Schnarr, M.1  Bertrand-Burggraf, E.1  | |
[1] Institut de Biologie Moléculaire et Cellulaire du CNRS, Laboratoire de Biophysique, 15 rue René-Descartes, 67084 Strasbourg Cédex, France | |
关键词: Regulation; Transcription initiation; RNA polymerase; Supercoiling; Fluorescence; Stopped-flow; | |
DOI : 10.1016/0014-5793(87)80118-7 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
In order to follow the fast kinetics of abortive initiation (lag time from 1 ms to 10 s), we have built a stopped-flow apparatus equipped for fluorescence detection. The small volume used for each assay (35 μl), and the short dead time (∼0.5 ms) are the essential advantages of this apparatus. Supercoiling of DNA affects considerably the initiation of transcription from the uvrA promoter. It decreases the lag time due to the isomerisation process 3-fold. Nevertheless, it does not change significantly the product K B k 2, which is indicative of promoter strength and shows that uvrA is an ‘association-limited’ promoter. The presence of the LexA repressor increases the lag time considerably. At least for small RNA polymerase concentrations this increase is stronger for supercoiled than for linearized DNA.
【 授权许可】
Unknown
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