An Asymmetry-to-Symmetry Switch in Signal Transmission by the Histidine Kinase Receptor for TMAO
- Columbia
The osmoregulator trimethylamine-N-oxide (TMAO), commonplace in aquatic organisms, is used as the terminal electron acceptor for respiration in many bacterial species. The TMAO reductase (Tor) pathway for respiratory catalysis is controlled by a receptor system that comprises the TMAO-binding protein TorT, the sensor histidine kinase TorS, and the response regulator TorR. Here we study the TorS/TorT sensor system to gain mechanistic insight into signaling by histidine kinase receptors. We determined crystal structures for complexes of TorS sensor domains with apo TorT and with TorT (TMAO); we characterized TorS sensor associations with TorT in solution; we analyzed the thermodynamics of TMAO binding to TorT-TorS complexes; and we analyzed in vivo responses to TMAO through the TorT/TorS/TorR system to test structure-inspired hypotheses. TorS-TorT(apo) is an asymmetric 2:2 complex that binds TMAO with negative cooperativity to form a symmetric active kinase.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- NIH
- OSTI ID:
- 1041332
- Journal Information:
- Structure, Journal Name: Structure Journal Issue: (4) ; 04, 2012 Vol. 20
- Country of Publication:
- United States
- Language:
- ENGLISH
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