THE FLHD FLHC COMPLEX, A TRANSCRIPTIONAL ACTIVATOR OF THE ESCHERICHIA-COLI FLAGELLAR CLASS-II OPERONS

Citation
Xy. Liu et P. Matsumura, THE FLHD FLHC COMPLEX, A TRANSCRIPTIONAL ACTIVATOR OF THE ESCHERICHIA-COLI FLAGELLAR CLASS-II OPERONS, Journal of bacteriology, 176(23), 1994, pp. 7345-7351
Citations number
31
Categorie Soggetti
Microbiology
Journal title
ISSN journal
00219193
Volume
176
Issue
23
Year of publication
1994
Pages
7345 - 7351
Database
ISI
SICI code
0021-9193(1994)176:23<7345:TFFCAT>2.0.ZU;2-G
Abstract
The Escherichia coli flhD operon encodes two genes, flhD and flhC. Bot h gene products were overproduced and purified. The purified proteins formed a complex consisting of two FlhD and two FlhC molecules. Mobili ty shift assays showed that the FlhD/FlhC complex had a DNA-binding ac tivity and bound to the upstream regions of fliA, flhB, and fliL opero ns (class II), which are under direct control of the flhD operon. DNas e I footprinting analyses of FlhD/FlhC binding to the three class II p romoter regions revealed protection of a 48-bp region of the fliA oper on between positions -41 to -88, a 50-bp region of the flhB operon bet ween positions -28 to -77, and a 48-bp region of the fliL operon betwe en positions -29 to -76. In vitro transcription experiments demonstrat ed that the FlhD/FlhC complex is a transcriptional activator required for the transcription of the three class II operons examined in vitro.