2kb1

NMR studies of a channel protein without membrane: structure and dynamics of water-solubilized KcsA

spinqualitylabelsall models 2kb1 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2kb1 is a 4 chain structure with sequence from Escherichia coli. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Structural studies of polytopic membrane proteins are often hampered by the vagaries of these proteins in membrane mimetic environments and by the difficulties in handling them with conventional techniques. Designing and creating water-soluble analogues with preserved native structures offer an attractive alternative. We report here solution NMR studies of WSK3, a water-soluble analogue of the potassium channel KcsA. The WSK3 NMR structure (PDB ID code 2K1E) resembles the KcsA crystal structures, validating the approach. By more stringent comparison criteria, however, the introduction of several charged residues aimed at improving water solubility seems to have led to the possible formations of a few salt bridges and hydrogen bonds not present in the native structure, resulting in slight differences in the structure of WSK3 relative to KcsA. NMR dynamics measurements show that WSK3 is highly flexible in the absence of a lipid environment. Reduced spectral density mapping and model-free analyses reveal dynamic characteristics consistent with an isotropically tumbling tetramer experiencing slow (nanosecond) motions with unusually low local ordering. An altered hydrogen-bond network near the selectivity filter and the pore helix, and the intrinsically dynamic nature of the selectivity filter, support the notion that this region is crucial for slow inactivation. Our results have implications not only for the design of water-soluble analogues of membrane proteins but also for our understanding of the basic determinants of intrinsic protein structure and dynamics. NMR studies of a channel protein without membranes: structure and dynamics of water-solubilized KcsA.,Ma D, Tillman TS, Tang P, Meirovitch E, Eckenhoff R, Carnini A, Xu Y Proc Natl Acad Sci U S A. 2008 Oct 28;105(43):16537-42. Epub 2008 Oct 23. PMID:18948596 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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