1grm

REFINEMENT OF THE SPATIAL STRUCTURE OF THE GRAMICIDIN A TRANSMEMBRANE ION-CHANNEL (RUSSIAN)REFINEMENT OF THE SPATIAL STRUCTURE OF THE GRAMICIDIN A TRANSMEMBRANE ION-CHANNEL (RUSSIAN)

Structural highlights 1grm 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. NonStd Res: , , , Related: 1tk2, 2xdc, 1av2, 1bdw, 1c4d, 1gmk, 1jno, 1kqe, 1mag, 1mic, 1ng8, 1nrm, 1nru, 1nt5, 1jo3, 1jo4, 1nt6, 1tkq, 1w5u, 2izq, 3l8l, 1al4, 1alx, 1alz Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The spatial structure of the gramicidin A (GA) transmembrane ion-channel was refined on the base of cross-peak volumes measured in NOESY spectra (mixing time tau m = 100 and 200 ms). The refinement methods included the comparison of experimental cross-peak volumes with those calculated for low-energy GA conformations, dynamic averaging of the low-energy conformation set and restrained energy minimization. Accuracy of the spatial structure determination was estimated by the penalty function Fr defined as a root mean square deviation of interproton distances corresponding to the calculated and experimental cross-peak volumes. As the initial conformation we used the right-handed pi 6,3 LD pi 6,3 LD helix established on the base of NMR data regardless of the cross-peak volumes. The conformation is in a good agreement with NOE cross-peak volumes (Fr 0.2 to 0.5 A depending on NOESY spectrum). For a number of NOEs formed by the side chain protons, distances errors were found as much as 0.5-2.0 A. Restrained energy minimization procedure had little further success. However some of these errors were eliminated by the change in torsional angle chi 2 of D-Leu12 and dynamic averaging of the Val7 side chain conformations. Apparently, majority of deviations of the calculated and experimental cross-peak volumes are due to the intramolecular mobility of GA and cannot be eliminated within the framework of rigid globule model. In summary the spatial structure of GA ion-channel can be thought as a set of low-energy conformations, differing by the side chain torsion angles chi 1 Val7 and chi 2 D-Leu4 and D-Leu10 and the orientation of the C-terminal ethanolamine group. Root mean square differences between the atomic coordinates of conformations are in the range of 0.3-0.8 A. [Refinement of the spatial structure of the gramicidin A ion channel],Lomize AL, Orekhov VIu, Arsen'ev AS Bioorg Khim. 1992 Feb;18(2):182-200. PMID:1376600 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Gramicidin

spinqualitylabelsall models 1grm, 5 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image