8T85

Structure of RssB bound to beryllofluoride

Summary for 8T85

• Entry DOI: 10.2210/pdb8t85/pdb
• Descriptor: Regulator of RpoS, DI(HYDROXYETHYL)ETHER, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: receiver domain, pseudophosphatase, response regulator, signaling protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 37746.77

Authors

Brugger, C.,Schwartz, J.,Deaconescu, A.M. (deposition date: 2023-06-21, release date: 2024-01-17)

Primary citation

Brugger, C.,Schwartz, J.,Novick, S.,Tong, S.,Hoskins, J.R.,Majdalani, N.,Kim, R.,Filipovski, M.,Wickner, S.,Gottesman, S.,Griffin, P.R.,Deaconescu, A.M.
Structure of phosphorylated-like RssB, the adaptor delivering sigma s to the ClpXP proteolytic machinery, reveals an interface switch for activation.
J.Biol.Chem., 299:105440-105440, 2023

PubMed Abstract: In enterobacteria such as Escherichia coli, the general stress response is mediated by σ, the stationary phase dissociable promoter specificity subunit of RNA polymerase. σ is degraded by ClpXP during active growth in a process dependent on the RssB adaptor, which is thought to be stimulated by the phosphorylation of a conserved aspartate in its N-terminal receiver domain. Here we present the crystal structure of full-length RssB bound to a beryllofluoride phosphomimic. Compared to the structure of RssB bound to the IraD anti-adaptor, our new RssB structure with bound beryllofluoride reveals conformational differences and coil-to-helix transitions in the C-terminal region of the RssB receiver domain and in the interdomain segmented helical linker. These are accompanied by masking of the α4-β5-α5 (4-5-5) "signaling" face of the RssB receiver domain by its C-terminal domain. Critically, using hydrogen-deuterium exchange mass spectrometry, we identify σ-binding determinants on the 4-5-5 face, implying that this surface needs to be unmasked to effect an interdomain interface switch and enable full σ engagement and hand-off to ClpXP. In activated receiver domains, the 4-5-5 face is often the locus of intermolecular interactions, but its masking by intramolecular contacts upon phosphorylation is unusual, emphasizing that RssB is a response regulator that undergoes atypical regulation.

PubMed: 37949227
DOI: 10.1016/j.jbc.2023.105440

Experimental method

X-RAY DIFFRACTION (2.38 Å)