Asymmetry of movements in CFTR's two ATP sites during pore opening serves their distinct functions
| Autor: | László Csanády, Ben Sorum, Beáta Töröcsik |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Patch-Clamp Techniques QH301-705.5 Protein Conformation Science Structural Biology and Molecular Biophysics Xenopus Mutant Cystic Fibrosis Transmembrane Conductance Regulator Gating General Biochemistry Genetics and Molecular Biology cystic fibrosis 03 medical and health sciences Xenopus laevis Adenosine Triphosphate ATP hydrolysis deltaF508 Animals Humans Nucleotide Biology (General) chemistry.chemical_classification General Immunology and Microbiology biology General Neuroscience Hydrolysis REFER E. coli asymmetric ABC protein General Medicine biology.organism_classification 030104 developmental biology R117H Structural biology Biochemistry chemistry Cytoplasm Chloride channel Biophysics Oocytes Medicine Protein Multimerization Protein Binding Research Article |
| Zdroj: | eLife eLife, Vol 6 (2017) |
| ISSN: | 2050-084X |
| Popis: | CFTR, the chloride channel mutated in cystic fibrosis (CF) patients, is opened by ATP binding to two cytosolic nucleotide binding domains (NBDs), but pore-domain mutations may also impair gating. ATP-bound NBDs dimerize occluding two nucleotides at interfacial binding sites; one site hydrolyzes ATP, the other is inactive. The pore opens upon tightening, and closes upon disengagement, of the catalytic site following ATP hydrolysis. Extent, timing, and role of non-catalytic-site movements are unknown. Here we exploit equilibrium gating of a hydrolysis-deficient mutant and apply Φ value analysis to compare timing of opening-associated movements at multiple locations, from the cytoplasmic ATP sites to the extracellular surface. Marked asynchrony of motion in the two ATP sites reveals their distinct roles in channel gating. The results clarify the molecular mechanisms of functional cross-talk between canonical and degenerate ATP sites in asymmetric ABC proteins, and of the gating defects caused by two common CF mutations. |
| Databáze: | OpenAIRE |
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