1abt
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(New page: 200px<br /><applet load="1abt" size="450" color="white" frame="true" align="right" spinBox="true" caption="1abt" /> '''NMR SOLUTION STRUCTURE OF AN ALPHA-BUNGAROTO...)
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Revision as of 08:37, 20 November 2007
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NMR SOLUTION STRUCTURE OF AN ALPHA-BUNGAROTOXIN(SLASH)NICOTINIC RECEPTOR PEPTIDE COMPLEX
Overview
We 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.
About this Structure
1ABT is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
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
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