An Autoinhibited State in the Structure of Thermotoga Maritima Nusg.
Drogemuller, J., Stegmann, C.M., Mandal, A., Steiner, T., Burmann, B.M., Gottesman, M.E., Wohrl, B.M., Rosch, P., Wahl, M.C., Schweimer, K.(2013) Structure 21: 365
- PubMed: 23415559 
- DOI: https://doi.org/10.1016/j.str.2012.12.015
- Primary Citation of Related Structures:  
2LQ8, 2XHA, 2XHC - PubMed Abstract: 
NusG is a conserved regulatory protein interacting with RNA polymerase (RNAP) and other proteins to form multicomponent complexes that modulate transcription. The crystal structure of Thermotoga maritima NusG (TmNusG) shows a three-domain architecture, comprising well-conserved amino-terminal (NTD) and carboxy-terminal (CTD) domains with an additional, species-specific domain inserted into the NTD. NTD and CTD directly contact each other, occluding a surface of the NTD for binding to RNAP and a surface on the CTD interacting either with transcription termination factor Rho or transcription antitermination factor NusE. NMR spectroscopy confirmed the intramolecular NTD-CTD interaction up to the optimal growth temperature of Thermotoga maritima. The domain interaction involves a dynamic equilibrium between open and closed states and contributes significantly to the overall fold stability of the protein. Wild-type TmNusG and deletion variants could not replace endogenous Escherichia coli NusG, suggesting that the NTD-CTD interaction of TmNusG represents an autoinhibited state.
Organizational Affiliation: 
Lehrstuhl Biopolymere und Forschungszentrum für Biomakromoleküle, Universität Bayreuth, Universitätsstrasse 30, Bayreuth, Germany.