Amino acid residues lining the chloride channel of the cystic fibrosis transmembrane conductance regulator
| Autor: | M H, Akabas, C, Kaufmann, T A, Cook, P, Archdeacon |
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| Rok vydání: | 1994 |
| Předmět: |
DNA
Complementary Base Sequence Cystic Fibrosis Molecular Sequence Data Cystic Fibrosis Transmembrane Conductance Regulator Membrane Proteins Protein Structure Secondary Recombinant Proteins Xenopus laevis Chloride Channels Mutagenesis Site-Directed Animals Humans Amino Acid Sequence Amino Acids Cloning Molecular |
| Zdroj: | The Journal of biological chemistry. 269(21) |
| ISSN: | 0021-9258 |
| Popis: | The cystic fibrosis transmembrane conductance regulator forms a chloride channel that is regulated by phosphorylation and intracellular ATP levels. The structure of the channel-forming domains is undetermined. To identify the residues lining this channel we substituted cysteine, one at a time, for 9 consecutive residues (91-99) in the M1 membrane-spanning segment. The cysteine substitution mutants were expressed in Xenopus oocytes. We determined the accessibility of the engineered cysteine to charged, sulfhydryl-specific methanethiosulfonate reagents added extracellularly. We assume that, among residues in membrane-spanning segments, only those lining the channel will be accessible to react with these hydrophilic reagents and that such a reaction would irreversibly alter conduction through the channel. Only the cysteines substituted for Gly-91, Lys-95, and Gln-98 were accessible to the reagents. We conclude that these residues are in the channel lining. The periodicity of these residues is consistent with an alpha-helical secondary structure. |
| Databáze: | OpenAIRE |
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