8BGB

Structure of the citrate-bound extracytoplasmic PAS domain of histidine kinase CitA from Geobacillus thermodenitrificans

This is a non-PDB format compatible entry.

Summary for 8BGB

• Entry DOI: 10.2210/pdb8bgb/pdb
• Descriptor: Histidine kinase, CITRATE ANION, SODIUM ION, ... (4 entities in total)
• Functional Keywords: pas domain, extracytoplasmic, citrate-bound, sensor histidine kinase, signaling protein
• Biological source: Geobacillus thermodenitrificans
• Total number of polymer chains: 8
• Total formula weight: 114545.01

Authors

Becker, S. (deposition date: 2022-10-27, release date: 2023-11-08, Last modification date: 2026-03-04)

Primary citation

Zhang, X.C.,Xue, K.,Salvi, M.,Schomburg, B.,Mehrens, J.,Giller, K.,Stopp, M.,Weisenburger, S.,Boning, D.,Sandoghdar, V.,Unden, G.,Becker, S.,Andreas, L.B.,Griesinger, C.
Mechanism of sensor kinase CitA transmembrane signaling.
Nat Commun, 16:935-935, 2025

PubMed Abstract: Membrane bound histidine kinases (HKs) are ubiquitous sensors of extracellular stimuli in bacteria. However, a uniform structural model is still missing for their transmembrane signaling mechanism. Here, we used solid-state NMR in conjunction with crystallography, solution NMR and distance measurements to investigate the transmembrane signaling mechanism of a paradigmatic citrate sensing membrane embedded HK, CitA. Citrate binding in the sensory extracytoplasmic PAS domain (PASp) causes the linker to transmembrane helix 2 (TM2) to adopt a helical conformation. This triggers a piston-like pulling of TM2 and a quaternary structure rearrangement in the cytosolic PAS domain (PASc). Crystal structures of PASc reveal both anti-parallel and parallel dimer conformations. An anti-parallel to parallel transition upon citrate binding agrees with interdimer distances measured in the lipid embedded protein using a site-specific F label in PASc. These data show how Angstrom scale structural changes in the sensor domain are transmitted across the membrane to be converted and amplified into a nm scale shift in the linker to the phosphorylation subdomain of the kinase.

PubMed: 39843904
DOI: 10.1038/s41467-024-55671-3

Experimental method

X-RAY DIFFRACTION (1.7 Å)