Location of close contacts between Escherichia coli RNA polymerase and guanine residues at promoters either with or without consensus -35 region sequences.
Methylation-interference assays have been used to identify guanine residues that make important contacts with RNA polymerase during open-complex formation at two related Escherichia coli promoters. Methylation of lower-strand G-31 at a gal consensus promoter completely prevents complex formation, while modification of upper-strand G-33 has no detectable effect. At galP1, which lacks a consensus -35 region, modification of lower-strand G-33 and upper-strand G-14 reduces, but does not prevent, complex formation. G-33 is the only guanine residue in the -35 region of galP1 where modification interferes with open-complex formation. Since this guanine residue is not protected in open complexes, we conclude that its modification causes alteration of, or interference with, a transient contact during the transcription initiation pathway.
Minchin
S
S
School of Biochemistry, University of Birmingham, U.K.
Busby
S
S
D001482:Base Composition; D001483:Base Sequence; D016384:Consensus Sequence; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005690:Galactose / Q000378:metabolism; D006147:Guanine; D007763:Lac Operon / Q000235:genetics*; D008745:Methylation; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D006147:Guanine; D012321:DNA-Directed RNA Polymerases; D005690:Galactose