Alpha-toxin binding to acetylcholine receptor alpha 179-191 peptides: intrinsic fluorescence studies.
Interactions between two alpha-toxins and the synthetic peptides alpha 179-191 from both calf and human acetylcholine receptor alpha-subunit sequences have been studied by measurements of quenching of intrinsic fluorescence after toxin addition. Dissociation constants of approx. 5 x 10(-8) M for binding of calf peptide by both alpha-cobratoxin and erabutoxin a have been estimated. The binding of alpha-cobratoxin to calf peptide, which leads to marked quenching of fluorescence intensity, is inhibited by a 10(4) molar excess of acetylcholine. The human alpha 179-191 peptide binds to alpha-cobratoxin, but not, under comparable conditions, to erabutoxin a.
Radding
W
W
Department of Biochemistry and Molecular Biophysics, Howard Hughes Institute, New York, NY.
Corfield
P W
PW
Levinson
L S
LS
Hashim
G A
GA
Low
B W
BW
D000818:Animals; D002417:Cattle; D003039:Cobra Neurotoxin Proteins / Q000378:metabolism*; D017937:Cytochrome d Group; D003580:Cytochromes / Q000378:metabolism*; D004546:Elapid Venoms / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004870:Erabutoxins / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D011485:Protein Binding; D011950:Receptors, Cholinergic / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D003039:Cobra Neurotoxin Proteins; D003580:Cytochromes; D004546:Elapid Venoms; D046911:Macromolecular Substances; D011950:Receptors, Cholinergic; D004870:Erabutoxins; C025154:alpha-cobratoxin; D017937:Cytochrome d Group; D003576:Electron Transport Complex IV