Structure of a voltage-dependent K+ channel beta subunit

Cell. 1999 Jun 25;97(7):943-52. doi: 10.1016/s0092-8674(00)80805-3.


The integral membrane subunits of many voltage-dependent potassium channels are associated with an additional protein known as the beta subunit. One function of beta subunits is to modify K+ channel gating. We have determined the structure of the conserved core of mammalian beta subunits by X-ray crystallography at 2.8 A resolution. Like the integral membrane component of K+ channels, beta subunits form a four-fold symmetric structure. Each subunit is an oxidoreductase enzyme complete with a nicotinamide co-factor in its active site. Several structural features of the enzyme active site, including its location with respect to the four-fold axis, imply that it may interact directly or indirectly with the K+ channel's voltage sensor. This structure suggests a mechanism for coupling membrane electrical excitability directly to chemistry of the cell.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Crystallography, X-Ray
  • Electric Conductivity
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Potassium Channels / chemistry*
  • Protein Conformation
  • Sequence Homology, Amino Acid


  • Potassium Channels

Associated data