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Interaction of modified neurotoxins from Naja nigricollis with the nicotinic acetylcholine receptor from Torpedo marmorata A Raman spectroscopy study
Author(s) -
Michel Négrerie,
Dimitrina Aslanian,
Françoise Bouet,
Andre Ménèz,
HoàngOanh Nghiêm,
JeanPierre Changeux
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80877-6
Subject(s) - torpedo , acetylcholine receptor , nicotinic acetylcholine receptor , chemistry , binding site , acetylcholine , receptor , neurotoxin , biophysics , toxin , biochemistry , stereochemistry , biology , endocrinology
Two derivatives of α‐toxin from Naja nigricollis venom were used in order to study, by resonance Raman spectroscopy, its interaction with the nicotinic acetylcholine (AcCho) receptor from membranes of Torpedo marmorata electrocytes. The two modified toxins carry either an NO 2 group bound to Tyr 25 or a nitrophenylthioether (NPS) bound to Trp 25 . The comparison of the spectra of the free and bound derivatized toxins indicates that the environment of Tyr 25 is not perturbed upon binding to the AcCho receptor, but the surroundings of NPS bound to Trp 29 are changed. This result indicates that Tyr 25 is not involved in binding, while Trp 29 of the α‐toxin may be in contact with the AcCho receptor. Examination of the spectrum of the AcCho receptor membrane after binding of the NPS‐Trp toxin discloses some modifications of the vibrations of the tryptophan and cysteine disulfide bridge of the receptor. These residues are possibly involved in toxin binding.