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Sequence‐directed DNA bending upstream of the streptokinase promoter
Author(s) -
Müller Jörg,
Malke Horst
Publication year - 1989
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620290913
Subject(s) - microbiology and biotechnology , dna , promoter , biology , gene , nucleic acid sequence , escherichia coli , coding region , gel electrophoresis , base pair , genetics , gene expression
A 450‐base pair (bp) Hin fI restriction fragment from the chromosome of Streptococcus equisimilis H46A contains the early coding region of the streptokinase gene ( skc ), the skc promoter, and a stretch of DNA 5′ to the – 35 region of the skc promoter. Two‐dimensional polyacrylamide (PA) gel electrophoresis at two different temperatures showed that this fragment migrates anomalously slowly on PA gels, suggesting the existence of a bent DNA conformation. Inspection of the nucleotide sequence confirmed this suggestion by revealing numerous oligomeric dA.dT tracts, some of which are in phase with the helix screw. Computer analysis of the sequence predicted the existence of two bending loci, one of which is located upstream of the skc promoter. In addition to showing DNA bending, the 450‐bp Hin fI fragment contains multiple 13‐bp sequences homologous to the Escherichia coli integration host factor DNA‐binding consensus sequence. Insertion of IS 1 into a site immediately upstream of the – 35 region decreased the expression level of skc in E. coli , suggesting that DNA conformation upstream of the promoter has a role in skc expression.