Guanosine Tetraphosphate Has a Similar Affinity for Each of Its Two Binding Sites on Escherichia coli RNA Polymerase.

ABSTRACT: During nutrient deprivation, the bacterial cell undergoes a stress response known as the stringent response. This response is characterized by induction of the nucleotide derivative guanosine tetraphosphate (ppGpp) that dramatically modulates the cell's transcriptome. In Escherichia coli, ppGpp regulates transcription of as many as 750 genes within 5 min of induction by binding directly to RNA polymerase (RNAP) at two sites ~60 Å apart. One proposal for the presence of two sites is that they have different affinities for ppGpp, expanding the dynamic range over which ppGpp acts. We show here, primarily using the Differential Radial Capillary Action of Ligand Assay (DRaCALA), that ppGpp has a similar affinity for each site, contradicting the proposal. Because the ppGpp binding sites a

SUBMITTER: Myers AR 

PROVIDER: S-EPMC7676912 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature