Sequence and properties of operator mutations in the bio operon of Escherichia coli.

摘要: The nucleotide-sequence changes occurring in newly isolated operator-constitutive mutations of the divergently transcribed bio operon have been determined. observed point are single GC leads to AT which occur at two symmetrical points hyphenated inverted repeat present control region. position -15 (with respect center repeat) cause constitutivity leftward expression and decreased bioB, due alteration -35 region rightward promoter. change +15 is identical one that Otsuka Abelson (1978) detected p98 o34 double mutant. location p131::IS1 insertion, affects both transcription, also within operator Both p131 insertion repressor binding vivo as shown by titration tests on multicopy plasmids bear them. decrease vitro, where added fails protect TaqI site protected o+ DNA. These results confirm several aspects model for regulation proposed (1978).