1mtx

DETERMINATION OF THE THREE-DIMENSIONAL STRUCTURE OF MARGATOXIN BY 1H, 13C, 15N TRIPLE-RESONANCE NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

spinqualitylabelsall models 1mtx Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1mtx is a 1 chain structure with sequence from Centruroides margaritatus. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 23 models Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KAX22_CENMA Potent selective inhibitor of voltage-dependent potassium channels such as Kv1.3/KCNA3. 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 PubMed The solution structure of the 39-residue peptide margatoxin, a scorpion toxin that selectively blocks the voltage-gated potassium-channel Kv1.3, has been determined by NMR spectroscopy. The toxin was isotopically labeled with 13C and 15N and studied using two-dimensional homonuclear and three- and four-dimensional heteronuclear NMR spectroscopy. The final structure was determined using 501 constraints, comprising 422 NOE constraints, 60 dihedral angle constraints, 9 disulfide constraints, and 10 hydrogen bond constraints. Structures were initially determined with the program PEGASUS and subsequently refined with X-PLOR. The average rms deviation from a calculated average structure for the backbone atoms of residues 3-38 is 0.40 A. A helix is present from residues 11 to 20 and includes two proline residues at positions 15 and 16. A loop at residues 21-24 leads into a two-strand antiparallel sheet from residues 25 to 38 with a turn at residues 30-33. Residues 3-6 run adjacent to the 33-38 strand but do not form a canonical beta-strand. The two additional residues of margatoxin, relative to the related toxins charybdotoxin and iberiotoxin, insert in a manner that extends the beta-sheet by one residue. Otherwise, the global structure is very similar to that of these two other toxins. The longer sheet may have implications for channel selectivity. Determination of the three-dimensional structure of margatoxin by 1H, 13C, 15N triple-resonance nuclear magnetic resonance spectroscopy.,Johnson BA, Stevens SP, Williamson JM Biochemistry. 1994 Dec 20;33(50):15061-70. PMID:7999764 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Potassium channel toxin 3D structures

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