1tkq

SOLUTION STRUCTURE OF A LINKED UNSYMMETRIC GRAMICIDIN IN A MEMBRANE-ISOELECTRICAL SOLVENTS MIXTURE IN THE PRESENCE OF CsCl

spinqualitylabelsall models 1tkq Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1tkq is a 2 chain structure with sequence from Brevibacillus brevis. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 1 model Ligands: DLE, DVA, SIN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The biological ion channel gramicidin A (gA) was modified by synthetic means to obtain the tail-to-tail linked asymmetric gA-derived dimer compound 3. Single-channel current measurements for 3 in planar lipid bilayers exhibit an Eisenman I ion selectivity for alkali cations. The structural asymmetry does not lead to an observable functional asymmetry. The structure of 3 in solution without and with Cs cations was investigated by 1H-NMR spectroscopy. In CDCl3/CD3OH (1 : 1, v/v), 3 forms a mixture of double-stranded beta-helices. Upon addition of excess CsCl, the double-stranded species are converted completely into one new conformer: the right-handed single-stranded beta-helix. A combination of DQF-COSY and TOCSY was used for the assignment of the 1H-NMR spectrum of the Cs-3 complex in CDCl3/CD3OH (1 : 1, v/v). A total of 69 backbone, 27 long-range, and 64 side-chain distance restraints were obtained from NOESY together with 25 phi and 14 chi1 torsion angles obtained from coupling constants. These data were used as input for structure calculation with dyana built in sybyl 6.8. A final set of 11 structures with an average rmsd for the backbone of 0.45 A was obtained (PDB: 1TKQ). The structure of the Cs-3 complex in solution is equivalent to the bioactive channel conformation in the membrane environment. An asymmetric ion channel derived from gramicidin A. Synthesis, function and NMR structure.,Xie X, Al-Momani L, Reiss P, Griesinger C, Koert U FEBS J. 2005 Feb;272(4):975-86. PMID:15691331 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Gramicidin

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