Regulation of the transcriptional activator NtrC1: structural studies of the regulatory and AAA+ ATPase domains.

Journal Article (Journal Article)

Transcription by sigma54 RNA polymerase depends on activators that contain ATPase domains of the AAA+ class. These activators, which are often response regulators of two-component signal transduction systems, remodel the polymerase so that it can form open complexes at promoters. Here, we report the first crystal structures of the ATPase domain of an activator, the NtrC1 protein from the extreme thermophile Aquifex aeolicus. This domain alone, which is active, crystallized as a ring-shaped heptamer. The protein carrying both the ATPase and adjacent receiver domains, which is inactive, crystallized as a dimer. In the inactive dimer, one residue needed for catalysis is far from the active site, and extensive contacts among the domains prevent oligomerization of the ATPase domain. Oligomerization, which completes the active site, depends on surfaces that are buried in the dimer, and hence, on a rearrangement of the receiver domains upon phosphorylation. A motif in the ATPase domain known to be critical for coupling energy to remodeling of polymerase forms a novel loop that projects from the middle of an alpha helix. The extended, structured loops from the subunits of the heptamer localize to a pore in the center of the ring and form a surface that could contact sigma54.

Full Text

Duke Authors

Cited Authors

  • Lee, S-Y; De La Torre, A; Yan, D; Kustu, S; Nixon, BT; Wemmer, DE

Published Date

  • October 15, 2003

Published In

Volume / Issue

  • 17 / 20

Start / End Page

  • 2552 - 2563

PubMed ID

  • 14561776

Pubmed Central ID

  • PMC218149

International Standard Serial Number (ISSN)

  • 0890-9369

Digital Object Identifier (DOI)

  • 10.1101/gad.1125603


  • eng

Conference Location

  • United States