Open this publication in new window or tab >>2009 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 48, no 25, p. 5813-5821Article in journal (Refereed) Published
Abstract [en]
Voltage-gated potassium channels open and close in response to changes in the membrane potential. In this study, we have determined the NMR solution structure of the putative S3b-S4 voltage-sensor paddle fragment, the part that moves to mediate voltage gating, of the HsapBK potassium channel in dodecylphosphocholine (DPC) micelles. This paper presents the first structure of the S3b-S4 fragment from a BK channel. Diffusion coefficients as determined from PFG NMR experiments showed that a well-defined complex between the peptide and DPC molecules was formed. The structure reveals a helix-turn-helix motif, which is in agreement with crystal structures of other voltage-gated potassium channels, thus indicating that it is feasible to study the isolated fragment. The paddle motifs generally contain several basic residues, implicated in the gating. The critical Arg residues in this structure all reside on the surface, which is in agreement with crystal structures of K(v) channels. Similarities in the structure of the S3b-S4 fragment in BK and K(v) channels as well as important differences are seen, which may be important for explaining the details in paddle movement within a bilayer.
Keywords
NMR solution structure, S3b−S4 fragment, paddle
National Category
Biophysics
Research subject
Biophysics; Biochemistry
Identifiers
urn:nbn:se:su:diva-31727 (URN)10.1021/bi9004599 (DOI)000267326500006 ()19456106 (PubMedID)
Funder
Swedish Research Council, 621-2011-5964
2009-11-252009-11-252022-02-28Bibliographically approved