3zrx
From Proteopedia
The high resolution structure of a dimeric Hamp-Dhp fusion displays strong asymmetry
Structural highlights
FunctionO28769_ARCFU ENVZ_ECOLI Member of the two-component regulatory system EnvZ/OmpR involved in the regulation of osmoregulation (genes ompF and ompC). EnvZ functions as a membrane-associated protein kinase that phosphorylates OmpR in response to environmental signals. Publication Abstract from PubMedBacterial transmembrane receptors regulate an intracellular catalytic output in response to extracellular sensory input. To investigate the conformational changes that relay the regulatory signal, we have studied the HAMP domain, a ubiquitous intracellular module connecting input to output domains. HAMP forms a parallel, dimeric, four-helical coiled coil, and rational substitutions in our model domain (Af1503 HAMP) induce a transition in its interhelical packing, characterized by axial rotation of all four helices (the gearbox signaling model). We now illustrate how these conformational changes are propagated to a downstream domain by fusing Af1503 HAMP variants to the DHp domain of EnvZ, a bacterial histidine kinase. Structures of wild-type and mutant constructs are correlated with ligand response in vivo, clearly associating them with distinct signaling states. We propose that altered recognition of the catalytic domain by DHp, rather than a shift in position of the phospho-accepting histidine, forms the basis for regulation of kinase activity. Mechanism of regulation of receptor histidine kinases.,Ferris HU, Dunin-Horkawicz S, Hornig N, Hulko M, Martin J, Schultz JE, Zeth K, Lupas AN, Coles M Structure. 2012 Jan 11;20(1):56-66. PMID:22244755[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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