Structural determinants within residues 180-199 of the rodent. alpha. 5 nicotinic acetylcholine receptor subunit involved in. alpha. -bungarotoxin binding

Journal Article · Mon Nov 04 23:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00108a018· OSTI ID:5559265

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

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

Synthetic peptides corresponding to sequence segments of the nicotinic acetylcholine receptor (nAChR) {alpha} subunits have been used to identify regions that contribute to formation of the binding sites for cholinergic ligands. The authors have previously defined {alpha}-bungarotoxin ({alpha}-BTX) binding sequences between residues 180 and 199 of a putative rat neuronal nAChR {alpha} subunit, designated {alpha}5, and between residues 181 and 200 of the chick neuronal {alpha}7 and {alpha}8 subunits. These sequences are relatively divergent compared with the Torpedo and muscle nAChR {alpha}1 {alpha}-BTX binding sites, which indicates a serious limitation of predicting functional domains of proteins based on homology in general. Given the highly divergent nature of the {alpha}5 sequence, they were interested in determining the critical amino acid residues for {alpha}-BTX binding. In the present study, the effects of single amino acid substitutions of Gly or Ala for each residue of the rat {alpha}(180-199) sequence were tested, using a competition assay, in which peptides compete for {sup 125}I-{alpha}-BTX binding with native Torpedo nAChR. These results indicate that a disulfide bridge between the vicinal cysteines at positions 191 and 192 of the {alpha}5 sequence is not an absolute requirement for {alpha}-BTX binding activity.

• OSTI ID: 5559265
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:44; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AMINES
AMINO ACID SEQUENCE
AMINO ACIDS
AMMONIUM COMPOUNDS
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CYSTEINE
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
HAZARDOUS MATERIALS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MATERIALS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PARASYMPATHOMIMETICS
PROTEINS
QUATERNARY COMPOUNDS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
THIOLS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES