1abt
From Proteopedia
NMR SOLUTION STRUCTURE OF AN ALPHA-BUNGAROTOXIN(SLASH)NICOTINIC RECEPTOR PEPTIDE COMPLEX
Structural highlights
Function[NXL1A_BUNMU] Binds with high affinity to muscular and neuronal (alpha-7, alpha-8, and alpha-9) nicotinic acetylcholine receptors. Produces peripheral paralysis by blocking neuromuscular transmission at the postsynaptic site. Blocks the extracellular increase of dopamine evoked by nicotine only at the higher dose (4.2 uM).[1] [2] [ACHA_TORCA] After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe report the two-dimensional nuclear magnetic resonance (NMR) characterization of the stoichiometric complex formed between the snake venom-derived long alpha-neurotoxin, alpha-bungarotoxin (BGTX), and a synthetic dodecapeptide (alpha 185-196) corresponding to a functionally important region on the alpha-subunit of the nicotinic acetylcholine receptor (nAChR) obtained from Torpedo californica electric organ tissue. BGTX has been widely used as the classic nicotinic competitive antagonist for the skeletal muscle type of nAChR which is found in the avian, amphibian, and mammalian neuromuscular junction. The receptor dodecapeptide (alpha 185-196) binds BGTX with micromolar affinity and has been shown to represent the major determinant of BGTX binding to the isolated alpha-subunit. Previous studies involving covalent modification of the native nAChR from Torpedo membranes with a variety of affinity reagents indicate that several residues contained within the dodecapeptide sequence (namely, Tyr-190, Cys-192, and Cys-193) apparently contribute directly to the formation of the cholinergic ligand binding site. The NMR-derived solution structure of the BGTX/receptor peptide complex defines a relatively extended conformation for a major segment of the "bound" dodecapeptide. These structural studies also reveal a previously unpredicted receptor binding cleft within BGTX and suggest that BGTX undergoes a conformational change upon peptide binding. If, as we hypothesize, the identified intermolecular contacts in the BGTX/receptor peptide complex describe a portion of the contact zone between BGTX and native receptor, then the structural data would suggest that alpha-subunit residues 186-190 are on the extracellular surface of the receptor. NMR solution structure of an alpha-bungarotoxin/nicotinic receptor peptide complex.,Basus VJ, Song G, Hawrot E Biochemistry. 1993 Nov 23;32(46):12290-8. PMID:8241115[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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