Abstract
To characterize the mechanism by which receptors propagate conformational changes across membranes, nitroxide spin labels were attached at strategic positions in the bacterial aspartate receptor. By collecting the electron paramagnetic resonance spectra of these labeled receptors in the presence and absence of the ligand aspartate, ligand binding was shown to generate an approximately 1 angstrom intrasubunit piston-type movement of one transmembrane helix downward relative to the other transmembrane helix. The receptor-associated phosphorylation cascade proteins CheA and CheW did not alter the ligand-induced movement. Because the piston movement is very small, the ability of receptors to produce large outcomes in response to stimuli is caused by the ability of the receptor-coupled enzymes to detect small changes in the conformation of the receptor.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Aspartic Acid / metabolism*
-
Bacterial Proteins / metabolism
-
Cell Membrane / metabolism*
-
Chemotaxis
-
Dimerization
-
Electron Spin Resonance Spectroscopy
-
Escherichia coli / metabolism
-
Escherichia coli Proteins*
-
Fourier Analysis
-
Histidine Kinase
-
Ligands
-
Lipid Bilayers
-
Membrane Proteins / metabolism
-
Methyl-Accepting Chemotaxis Proteins
-
Methylation
-
Models, Biological*
-
Mutagenesis
-
Phosphorylation
-
Protein Conformation
-
Protein Kinases / metabolism
-
Protein Structure, Secondary
-
Receptors, Amino Acid / chemistry*
-
Receptors, Amino Acid / genetics
-
Receptors, Amino Acid / metabolism*
-
Signal Transduction*
-
Spin Labels
Substances
-
Bacterial Proteins
-
CheW protein, E coli
-
Escherichia coli Proteins
-
Ligands
-
Lipid Bilayers
-
Membrane Proteins
-
Methyl-Accepting Chemotaxis Proteins
-
Receptors, Amino Acid
-
Spin Labels
-
aspartic acid receptor
-
CheW protein, Bacteria
-
Aspartic Acid
-
Protein Kinases
-
Histidine Kinase
-
cheA protein, E coli