Sequential multiple functions of the conserved sequence in sequence-specific termination by T7 RNA polymerase.

ABSTRACT: Escherichia coli rrnB terminator t1 contains an RNA hairpin-dependent (class I) and a sequence-specific (class II) termination signal. The latter consists of an 8-bp conserved sequence (CS), TATCTGTT, immediately followed by an 8-bp T rich sequence. In this study, elongation complexes of T7 RNA polymerase at various positions of the class II signal and several mutant signals were obtained by stepwise walking on immobilized DNA templates free of the class I signal. Multiple CS-associated conformational changes were observed, starting at the beginning of the signal and occurring sequentially. When the complexes reach the first base pair of the CS-DNA duplex, which is downstream of the RNA-DNA heteroduplex, their stability, as measured by time-course retention of radiolabeled transcripts, mar

SUBMITTER: Sohn Y 

PROVIDER: S-EPMC544054 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature