Conservation of chloride channel structure revealed by an inhibitor binding site in ClC-1

Neuron. 2003 Apr 10;38(1):47-59. doi: 10.1016/s0896-6273(03)00168-5.

Abstract

Crystal structures of bacterial CLC proteins were solved recently, but it is unclear to which level of detail they can be extrapolated to mammalian chloride channels. Exploiting the difference in inhibition by 9-anthracene carboxylic acid (9-AC) between ClC-0, -1, and -2, we identified a serine between helices O and P as crucial for 9-AC binding. Mutagenesis based on the crystal structure identified further residues affecting inhibitor binding. They surround a partially hydrophobic pocket close to the chloride binding site that is accessible from the cytoplasm, consistent with the observed intracellular block by 9-AC. Mutations in presumably Cl--coordinating residues yield additional insights into the structure and function of ClC-1. Our work shows that the structure of bacterial CLCs can be extrapolated with fidelity to mammalian Cl- channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthracenes / pharmacology
  • Binding Sites / drug effects
  • Binding Sites / genetics
  • Chloride Channels* / chemistry
  • Chloride Channels* / genetics
  • Chloride Channels* / metabolism
  • Conserved Sequence*
  • Humans
  • Ion Channel Gating / physiology
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed / physiology
  • Oocytes / physiology
  • Patch-Clamp Techniques
  • Protein Structure, Tertiary
  • Rats
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Serine / metabolism
  • Xenopus

Substances

  • Anthracenes
  • CLC-1 channel
  • Chloride Channels
  • ClC-2 chloride channels
  • Recombinant Fusion Proteins
  • Serine
  • 9-anthroic acid

Grant support