Abstract
The gating ring of cyclic nucleotide-modulated channels is proposed to be either a two-fold symmetric dimer of dimers or a four-fold symmetric tetramer based on high-resolution structure data of soluble cyclic nucleotide-binding domains and functional data on intact channels. We addressed this controversy by obtaining structural data on an intact, full-length, cyclic nucleotide-modulated potassium channel, MloK1, from Mesorhizobium loti, which also features a putative voltage-sensor. We present here the 3D single-particle structure by transmission electron microscopy and the projection map of membrane-reconstituted 2D crystals of MloK1 in the presence of cAMP. Our data show a four-fold symmetric arrangement of the CNBDs, separated by discrete gaps. A homology model for full-length MloK1 suggests a vertical orientation for the CNBDs. The 2D crystal packing in the membrane-embedded state is compatible with the S1-S4 domains in the vertical "up" state.
Original language | English (US) |
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Pages (from-to) | 1053-1064 |
Number of pages | 12 |
Journal | Structure |
Volume | 15 |
Issue number | 9 |
DOIs | |
State | Published - Sep 11 2007 |
Externally published | Yes |
Keywords
- CELLBIO
- MOLNEURO
- SIGNALING
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology