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TERTIARY STRUCTURE OF ERABUTOXIN B IN AQUEOUS SOLUTION ELUCIDATED BY TWO-DIMENSIONAL NUCLEAR MAGNETIC RESONANCE
Structural highlights
Function3S1EB_LATSE Binds with high affinity to muscular nicotinic acetylcholine receptors (nAChRs) (tested on Torpedo marmorata, Kd=0.07 nM), and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (tested on chimeric alpha-7/CHRNA7, Kd=22 uM) and inhibit acetylcholine from binding to the receptor, thereby impairing neuromuscular transmission (PubMed:7721859). Produces peripheral paralysis by blocking neuromuscular transmission at the postsynaptic site.[1] 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 PubMedThe three-dimensional structure of erabutoxin b, a short-chain neurotoxic peptide purified from the venom of the sea snake Laticauda semifasciata, was determined in aqueous solution by two-dimensional proton nuclear magnetic resonance and simulated annealing-based calculations. On the basis of 883 assigned nuclear Overhauser effect (NOE) connectivities, 676 final distance constraints were derived and used together with 38 torsion angle (phi, chi 1) constraints, four distance constraints derived from disulfide bridges and 30 distance constraints derived from hydrogen bonds. A total of 14 converged structures were obtained from 50 runs of calculations. The atomic root-mean-square difference about the mean coordinate positions (excluding the residues 18 to 22) is 0.60 A for backbone atoms (N, C alpha and C'). The protein consists of a core region from which three finger-like loops emerge outwards. It includes a short, two-stranded antiparallel beta-sheet of residues 2 to 5 and 13 to 16, a three-stranded antiparallel beta-sheet involving residues 23 to 30, 35 to 41 and 50 to 56, and four disulfide bridges in the core region. Comparison with two crystal structures of erabutoxin b at 1.4 A and 1.7 A resolution indicated that the solution and the crystal structures were very similar, but less defined regions were observed at the localized region of the tip of the central loop and the outside of the third loop in solution. Other short-chain alpha-neurotoxins showed structural characteristics similar to those of erabutoxin b. Tertiary structure of erabutoxin b in aqueous solution as elucidated by two-dimensional nuclear magnetic resonance.,Hatanaka H, Oka M, Kohda D, Tate S, Suda A, Tamiya N, Inagaki F J Mol Biol. 1994 Jul 8;240(2):155-66. PMID:8027999[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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