Mapping of a cholinergic binding site by means of synthetic peptides, monoclonal antibodies, and. alpha. -bungarotoxin

Journal Article · Tue Jul 03 04:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00478a016· OSTI ID:6290721

Conti-Tronconi, B M; Tang, Fen; Diethelm, B M; Spencer, S R ^[1]; Reinhardt-Maelicke, S; Maelicke, A ^[2]

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1. Univ. of Minnesota, St. Paul (USA)
2. Max-Planck-Institut fur Ernahrungsphysiologie, Dortmund (West Germany)

Previous studies by several laboratories have identified a narrow sequence region of the nicotinic acetylcholine receptor (AChR) {alpha} subunit, flanking the cysteinyl residues at positions 192 and 193, as containing major elements of, if not all, the binding site for cholinergic ligands. In the present study, the authors used a panel of synthetic peptides as representative structural elements of the AChR to investigate whether additional segments of the AChR sequences are able to bind {alpha}-bungarotoxin ({alpha}-BTX) and several {alpha}-BTX-competitive monoclonal antibodies (mAbs). The mAbs used (WF6, WF5, and W2) were raised against native Torpedo AChR, specifically recognize the {alpha}-subunit, and bind to AChR in a mutually exclusive fashion with {alpha}-BTX. The binding of WF5 and W2 to Torpedo AChR is inhibited by all cholinergic ligands. WF6 competes with agonists, but not with low mol. wt. antagonists, for AChR binding. Peptides {alpha}181-200 and {alpha}55-74 both inhibited binding of {sup 125}I-{alpha}-BTX to native Torpedo AChR. None of the peptides corresponding to sequence segments from other subunits bound {alpha}-BTX or WF6, or interfered with their binding. Therefore, the cholinergic binding site is not a single narrow sequence region, but rather two or more discontinuous sequence segments within the N-terminal extracellular region of the AChR {alpha} subunit, folded together in the native structure of the receptor, contribute to form a cholinergic binding region.

• OSTI ID: 6290721
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:26; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ACETYLCHOLINE
AMINES
AMINO ACID SEQUENCE
AMMONIUM COMPOUNDS
ANTIBODIES
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOASSAY
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGANDS
MATERIALS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
MONOCLONAL ANTIBODIES
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PARASYMPATHOMIMETICS
PEPTIDES
PROTEINS
QUATERNARY COMPOUNDS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES