Structural determinants of alpha-bungarotoxin binding to the sequence segment 181-200 of the muscle nicotinic acetylcholine receptor. alpha. subunit: Effects of cysteine/cystine modification and species-specific amino acid substitution

Journal Article · Tue May 21 04:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00234a013· OSTI ID:5014378

McLane, K E; Wu, Xiadong; Diethelm, B; Conti-Tronconi, B M ^[1]

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1. Univ. of Minnesota, St. Paul (United States)

The sequence segment 181-200 of the Torpedo nicotinic acetylcholine receptor (nAChR) {alpha}subunit forms a binding site for {alpha}-bungarotoxin ({alpha}-BTX). Synthetic peptides corresponding to the homologous sequences of human, calf, mouse, chicken, frog, and cobra muscle nAChR {alpha}1 subunits were tested for their ability to bind {sup 125}I-{alpha}-BTX, and differences in {alpha}-BTX affinity were determined by using solution (IC{sub 50}s) and solid-phase (K{sub d}s) assays. Panels of overlapping peptides corresponding to the complete {alpha}1 subunit of mouse and human were also tested for {alpha}-BTX binding, but other sequence segments forming the {alpha}-BTX site were not consistently detectable. The role of a putative vicinal disulfide bound between Cys-192 and -193, relative to the Torpedo sequence, was determined by modifying the peptides with sulfhydryl reagents. Reduction and alkylation of the peptides decreased {alpha}-BTX binding, whereas oxidation of the peptides had little effect. These results indicate that while the adjacent cysteines are likely to be involved in forming the toxin/{alpha}1-subunit interface a vicinal disulfide bound was not required for {alpha}-BTX binding.

• OSTI ID: 5014378
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:20; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

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550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ACETYLCHOLINE
AMINES
AMMONIUM COMPOUNDS
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIRDS
CALVES
CATTLE
CHEMICAL BONDS
CHICKENS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
FOWL
FROGS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MAN
MEMBRANE PROTEINS
MICE
MOLECULAR STRUCTURE
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PARASYMPATHOMIMETICS
PRIMATES
PROTEINS
QUATERNARY COMPOUNDS
RADIOISOTOPES
RADIORECEPTOR ASSAY
REACTION KINETICS
RECEPTORS
REPTILES
RODENTS
RUMINANTS
SNAKES
TRACER TECHNIQUES
VERTEBRATES