The Structure of the Prokaryotic Cyclic Nucleotide-Modulated Potassium Channel MloK1 at 16 Å Resolution

Po Lin Chiu, Matthew D. Pagel, James Evans, Hui Ting Chou, Xiangyan Zeng, Bryant Gipson, Henning Stahlberg, Crina M. Nimigean

Research output: Contribution to journalArticle

45 Scopus citations

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 languageEnglish (US)
Pages (from-to)1053-1064
Number of pages12
JournalStructure
Volume15
Issue number9
DOIs
StatePublished - Sep 11 2007
Externally publishedYes

Keywords

  • CELLBIO
  • MOLNEURO
  • SIGNALING

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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    Chiu, P. L., Pagel, M. D., Evans, J., Chou, H. T., Zeng, X., Gipson, B., Stahlberg, H., & Nimigean, C. M. (2007). The Structure of the Prokaryotic Cyclic Nucleotide-Modulated Potassium Channel MloK1 at 16 Å Resolution. Structure, 15(9), 1053-1064. https://doi.org/10.1016/j.str.2007.06.020