Download MendeleyStructural underpinnings of nitrogen regulation by the prototypical nitrogen-responsive transcriptional factor NrpR.
Wisedchaisri, G., Dranow, D.M., Lie, T.J., Bonanno, J.B., Patskovsky, Y., Ozyurt, S.A., Sauder, J.M., Almo, S.C., Wasserman, S.R., Burley, S.K., Leigh, J.A., Gonen, T.(2010) Structure 18: 1512-1521
- PubMed: 21070950
- DOI: https://doi.org/10.1016/j.str.2010.08.014
- Primary Citation of Related Structures:
3NEK - PubMed Abstract:
Plants and microorganisms reduce environmental inorganic nitrogen to ammonium, which then enters various metabolic pathways solely via conversion of 2-oxoglutarate (2OG) to glutamate and glutamine. Cellular 2OG concentrations increase during nitrogen starvation. We recently identified a family of 2OG-sensing proteins--the nitrogen regulatory protein NrpR--that bind DNA and repress transcription of nitrogen assimilation genes. We used X-ray crystallography to determine the structure of NrpR regulatory domain. We identified the NrpR 2OG-binding cleft and show that residues predicted to interact directly with 2OG are conserved among diverse classes of 2OG-binding proteins. We show that high levels of 2OG inhibit NrpRs ability to bind DNA. Electron microscopy analyses document that NrpR adopts different quaternary structures in its inhibited 2OG-bound state compared with its active apo state. Our results indicate that upon 2OG release, NrpR repositions its DNA-binding domains correctly for optimal interaction with DNA thereby enabling gene repression.
Organizational Affiliation:
Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.
