Engagement of arginine finger to ATP triggers large conformational changes in NtrC1 AAA+ ATPase for remodeling bacterial RNA polymerase.

ABSTRACT: The NtrC-like AAA+ ATPases control virulence and other important bacterial activities through delivering mechanical work to ?54-RNA polymerase to activate transcription from ?54-dependent genes. We report the first crystal structure for such an ATPase, NtrC1 of Aquifex aeolicus, in which the catalytic arginine engages the ?-phosphate of ATP. Comparing the new structure with those previously known for apo and ADP-bound states supports a rigid-body displacement model that is consistent with large-scale conformational changes observed by low-resolution methods. First, the arginine finger induces rigid-body roll, extending surface loops above the plane of the ATPase ring to bind ?54. Second, ATP hydrolysis permits Pi release and retraction of the arginine with a reversed roll, remodeling ?54-RNAP. This model provides a fresh perspective on how ATPase subunits interact within the ring-ensemble to promote transcription, directing attention to structural changes on the arginine-finger side of an ATP-bound interface.

SUBMITTER: Chen B 

PROVIDER: S-EPMC3001195 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature