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Temperature-dependence of open-complex formation at two Escherichia coli promoters with extended -10 sequences.

ABSTRACT: We have studied the formation of open complexes between purified RNA polymerase from Escherichia coli and DNA fragments carrying the galP1 promoter, a promoter with an extended -10 region. Unusually, these complexes are formed readily at low temperatures. This low-temperature opening is unaffected by deletions of either upstream or downstream promoter sequences. We conclude that low-temperature open-complex formation is due to specific base sequences in and just upstream of the extended -10 region. In contrast, open complexes are not formed at low temperatures with DNA fragments carrying the E. coli cysG promoter, which also has an extended -10 region. This demonstrates that an extended -10 sequence alone is not sufficient for low-temperature opening. Additionally, we report the temperature dependence of a hybrid galP1-cysG promoter, the related galP2 and galP3 promoters and a derivative of galP1 with an improved -10 hexamer sequence.

SUBMITTER: Burns HD

PROVIDER: S-EPMC1217479 | biostudies-other | 1996 Jul

REPOSITORIES: biostudies-other

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The Escherichia coli cysG promoter belongs to the 'extended -10' class of bacterial promoters.

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