Phosphorescence and ODMR study of the binding interactions of acetylcholine receptor alpha-subunit peptides with alpha-cobratoxin.
Optical detection of magnetic resonance (ODMR) and phosphorescence spectroscopy have been applied to synthetic peptides derived from the alpha-subunit of the nicotinic acetylcholine receptor of Torpedo californica and their complexes with alpha-cobratoxin (CBTX). The CBTX Trp phosphorescence is strongly quenched by the proximal disulfide linkage, while the emission wavelengths and ODMR frequencies of the 18-mer alpha 181-198 indicate a more hydrophobic Trp environment than in the 12-mer alpha 185-196. Binding to CBTX produces a subtle increase in the hydrophobicity of the Trp environment for the peptides, in qualitative agreement with a recently proposed binding model, in which a receptor Trp residue interacts strongly with a hydrophobic cleft of the toxin.
Tringali
A E
AE
Department of Chemistry, New York University, NY 10003.
Pearce
S F
SF
Hawrot
E
E
Brenner
H C
HC
D000818:Animals; D003039:Cobra Neurotoxin Proteins / Q000378:metabolism*; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D055095:Optics and Photonics; D010446:Peptide Fragments / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000378:metabolism*; D014101:Torpedo
D003039:Cobra Neurotoxin Proteins; D010446:Peptide Fragments; D011950:Receptors, Cholinergic; C025154:alpha-cobratoxin