Nucleotide recognition by the cytoplasmic domain of the human chloride transporter ClC-5.
The ubiquitous CBS domains, which are found as part of cytoplasmic domains in the ClC family of chloride channels and transporters, have previously been identified as building blocks for regulatory nucleotide-binding sites. Here we report the structures of the cytoplasmic domain of the human transporter ClC-5 in complex with ATP and ADP. The nucleotides bind to a specific site in the protein. As determined by equilibrium dialysis, the affinities for ATP, ADP and AMP are in the high micromolar range. Point mutations that interfere with nucleotide binding change the transport behavior of a ClC-5 mutant expressed in Xenopus laevis oocytes. Our results establish the structural and energetic basis for the interaction of ClC-5 with nucleotides and provide a framework for future investigations.
Meyer
Sebastian
S
Department of Biochemistry, University of Zurich, Winterthurer Strasse 190, CH-8057 Zurich, Switzerland.
Savaresi
Sara
S
Forster
Ian C
IC
Dutzler
Raimund
R
D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018118:Chloride Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004734:Energy Metabolism; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009865:Oocytes; D018408:Patch-Clamp Techniques; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014982:Xenopus laevis
D000227:Adenine Nucleotides; C097503:CLC-5 chloride channel; D018118:Chloride Channels; D008024:Ligands; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate