Bunch, H: ¿Q interaction with E. coli RNA polymerase foranti

Phage lambdaQ protein is a transcriptional antiterminatorthat is required for late gene expression from the pR‘ promoter when lambdaprophage decides to follow the lytic pathway. LambdaQ modifiesEscherichia coli RNA polymerase (RNAP) at the early elongation stage. Onceengaged, lambdaQ maintains itself as a subunit of the elongationcomplex throughout the elongation. Studies show that lambdaQ confers RNAPresistance to both intrinsic and rho-mediated terminators and lesspausing. However, little is known about the interactionbetween lambdaQ and RNAP. In this study, the largest subunits (ß and ß‘) ofRNAP were examined to map the lambdaQ binding site. A stronger binding wasobserved with ß than ß‘, and the binding site was narrowed toß501-832. This region was further defined as small as 82 amino acids(ß600-681) that interacted with lambdaQ. In addition, 12 mutant RNAPswere isolated for a reduced lambdaQ antitermination within the potentiallambdaQ binding regions, specifically near the main channel. Theseresults propose that lambdaQ modifies the active center of RNAP forantitermination.