The structure of the prokaryotic cyclic nucleotide-modulated potassium channel MloK1 at 16 A resolution. Academic Article uri icon

Overview

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.

publication date

  • September 1, 2007

Research

keywords

  • Cyclic AMP
  • Potassium Channels
  • Rhizobium

Identity

PubMed Central ID

  • PMC2000844

Scopus Document Identifier

  • 34548402962

Digital Object Identifier (DOI)

  • 10.1016/j.jmb.2007.1006.1030

PubMed ID

  • 17850745

Additional Document Info

volume

  • 15

issue

  • 9