2qto
From Proteopedia
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| , resolution 3.201Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Gene: | kcsA, skc1 (Streptomyces lividans) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
An anisotropic model for potassium channel KcsA
Overview
We report a normal-mode method for anisotropic refinement of membrane-protein structures, based on a hypothesis that the global near-native-state disordering of membrane proteins in crystals follows low-frequency normal modes. Thus, a small set of modes is sufficient to represent the anisotropic thermal motions in X-ray crystallographic refinement. By applying the method to potassium channel KcsA at 3.2 A, we obtained a structural model with an improved fit with the diffraction data. Moreover, the improved electron density maps allowed for large structural adjustments for 12 residues in each subunit, including the rebuilding of 3 missing side chains. Overall, the anisotropic KcsA structure at 3.2 A was systematically closer to a 2.0 A KcsA structure, especially in the selectivity filter. Furthermore, the anisotropic thermal ellipsoids from the refinement revealed functionally relevant structural flexibility. We expect this method to be a valuable tool for structural refinement of many membrane proteins with moderate-resolution diffraction data.
About this Structure
2QTO is a Single protein structure of sequence from Streptomyces lividans. Full crystallographic information is available from OCA.
Reference
Normal-mode refinement of anisotropic thermal parameters for potassium channel KcsA at 3.2 A crystallographic resolution., Chen X, Poon BK, Dousis A, Wang Q, Ma J, Structure. 2007 Aug;15(8):955-62. PMID:17698000
Page seeded by OCA on Thu Mar 20 18:29:27 2008
