The structural basis for regulated assembly and function of the transcriptional activator NtrC.
In two-component signal transduction, an input triggers phosphorylation of receiver domains that regulate the status of output modules. One such module is the AAA+ ATPase domain in bacterial enhancer-binding proteins that remodel the sigma(54) form of RNA polymerase. We report X-ray solution scattering and electron microscopy structures of the activated, full-length nitrogen-regulatory protein C (NtrC) showing a novel mechanism for regulation of AAA+ ATPase assembly via the juxtaposition of the receiver domains and ATPase ring. Accompanying the hydrolysis cycle that is required for transcriptional activation, we observed major order-disorder changes in the GAFTGA loops involved in sigma(54) binding, as well as in the DNA-binding domains.
De Carlo
Sacha
S
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA.
Chen
Baoyu
B
Hoover
Timothy R
TR
Kondrashkina
Elena
E
Nogales
Eva
E
Nixon
B Tracy
BT
D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000502:physiology*; D006868:Hydrolysis; D008854:Microscopy, Electron; D051922:PII Nitrogen Regulatory Proteins / Q000737:chemistry* / Q000502:physiology*; D010766:Phosphorylation; D012542:Scattering, Radiation; D015534:Trans-Activators / Q000737:chemistry* / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry* / Q000502:physiology*
D029968:Escherichia coli Proteins; D051922:PII Nitrogen Regulatory Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C497876:glnG protein, E coli