4I3M image
Deposition Date 2012-11-26
Release Date 2013-02-27
Last Version Date 2024-02-28
Entry Detail
PDB ID:
4I3M
Title:
Aer2 poly-HAMP domains: L44H HAMP1 CW-lock mutant
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.95 Å
R-Value Free:
0.25
R-Value Work:
0.20
Space Group:
P 32 1 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Aerotaxis transducer Aer2
Gene (Uniprot):mcpB
Mutations:L44H
Chain IDs:A
Chain Length:175
Number of Molecules:1
Biological Source:Pseudomonas aeruginosa
Primary Citation
HAMP Domain Conformers That Propagate Opposite Signals in Bacterial Chemoreceptors.
Plos Biol. 11 e1001479 e1001479 (2013)
PMID: 23424282 DOI: 10.1371/journal.pbio.1001479

Abstact

HAMP domains are signal relay modules in >26,000 receptors of bacteria, eukaryotes, and archaea that mediate processes involved in chemotaxis, pathogenesis, and biofilm formation. We identify two HAMP conformations distinguished by a four- to two-helix packing transition at the C-termini that send opposing signals in bacterial chemoreceptors. Crystal structures of signal-locked mutants establish the observed structure-to-function relationships. Pulsed dipolar electron spin resonance spectroscopy of spin-labeled soluble receptors active in cells verify that the crystallographically defined HAMP conformers are maintained in the receptors and influence the structure and activity of downstream domains accordingly. Mutation of HR2, a key residue for setting the HAMP conformation and generating an inhibitory signal, shifts HAMP structure and receptor output to an activating state. Another HR2 variant displays an inverted response with respect to ligand and demonstrates the fine energetic balance between "on" and "off" conformers. A DExG motif found in membrane proximal HAMP domains is shown to be critical for responses to extracellular ligand. Our findings directly correlate in vivo signaling with HAMP structure, stability, and dynamics to establish a comprehensive model for HAMP-mediated signal relay that consolidates existing views on how conformational signals propagate in receptors. Moreover, we have developed a rational means to manipulate HAMP structure and function that may prove useful in the engineering of bacterial taxis responses.

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Primary Citation of related structures