6ghb
Crystal structure of Spx in complex with YjbH (oxidized)
Structural highlights
FunctionSPX_BACSU Interferes with activator-stimulated transcription by interaction with the RNA polymerase alpha-CTD. May function to globally reduce transcription of genes involved in growth- and development-promoting processes and to increase transcription of genes involved in thiol homeostasis, during periods of extreme stress. Negatively affects competence and sporulation. Its degradation by the MecA/ClpXP complex is needed for competence development.[1] [2] Publication Abstract from PubMedYjbH is a bacterial adaptor protein required for efficient proteolysis of the RNA polymerase-binding transcription factor Spx by the ClpXP protease. We report the structure of YjbH in complex with Spx. YjbH comprises a DsbA-like thioredoxin domain connected via a linker to a C-terminal domain reminiscent of the winged helix-turn-helix fold. The interaction between YjbH and Spx involves a large surface area. Binding to YjbH stabilizes the C-terminal ClpX recognition region of Spx. We show that mutation of critical YjbH contact residues abrogates Spx recognition. Small-angle X-ray scattering and hydrogen-deuterium exchange mass spectrometry analyses determined the existence of a stable heterodimeric complex in solution and provide evidence that binding of Spx to YjbH reduces the overall conformational flexibility of Spx. Our findings provide insights into the molecular basis for Spx recognition and suggest a model for how YjbH stabilizes Spx and displays the C terminus of Spx for engagement by ClpXP. Structural Basis for YjbH Adaptor-Mediated Recognition of Transcription Factor Spx.,Awad W, Al-Eryani Y, Ekstrom S, Logan DT, von Wachenfeldt C Structure. 2019 Apr 3. pii: S0969-2126(19)30087-5. doi:, 10.1016/j.str.2019.03.009. PMID:30982633[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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