The Reduction in Sigma-Promoter Recognition Flexibility as Induced by Core is Required for Sigma to Discern the Optimal Promoter Spacing

We examined this issue using a transcriptionally active Bacillus subtilis N-terminally truncated σA (SND100-σA). Our results demonstrated that SND100-σA binds specifically to both -10 and -35 elements of the trnS spacing variants, of which the spacer lengths range from 14 to 21 bp, indicating that simultaneous and specific recognition of promoter -10 and -35 elements is insufficient for primary σ to discern the optimal promoter spacing. Moreover, shortening in length of the flexible linker between the two promoter DNA-binding domains of σA also does not enable SND100-σA to sense the optimal promoter spacing. Efficient recognition of optimal promoter spacing by SND100-σA requires core RNAP which reduces the flexibility of simultaneous and specific binding of SND100-σA to both promoter -10 and -35 elements. Thus, the discrimination of optimal promoter spacing by σ is core-dependent.

Source: BJ Gene - July 22, 2013 Category: Biochemistry Authors: H Yeh, H Hsu, T Chen, K Chung, K Liou, B Chang Tags: BJ Gene Source Type: research