1. Identification of binding sites for ivacaftor on the cystic fibrosis transmembrane conductance regulator
- Author
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Zhi-Wei Zeng, Zafar Qureshi, Robert N. Young, Christine E. Bear, Evgeniy V. Petrotchenko, Onofrio Laselva, Mohabir Ramjeesingh, Christoph H. Borchers, Ling-Jun Huan, Régis Pomès, and C. Michael Hamilton
- Subjects
0301 basic medicine ,congenital, hereditary, and neonatal diseases and abnormalities ,Science ,Biophysics ,Peptide ,02 engineering and technology ,Cystic fibrosis ,Biochemistry ,Article ,Ivacaftor ,03 medical and health sciences ,medicine ,Binding site ,chemistry.chemical_classification ,Multidisciplinary ,biology ,Biological membrane ,respiratory system ,021001 nanoscience & nanotechnology ,medicine.disease ,Cystic fibrosis transmembrane conductance regulator ,Transmembrane protein ,3. Good health ,Cell biology ,A-site ,Biological sciences ,030104 developmental biology ,chemistry ,biology.protein ,Medicine ,0210 nano-technology ,Structural biology ,medicine.drug - Abstract
Summary Ivacaftor (VX-770) was the first cystic fibrosis transmembrane conductance regulator (CFTR) modulatory drug approved for the treatment of patients with cystic fibrosis. Electron cryomicroscopy (cryo-EM) studies of detergent-solubilized CFTR indicated that VX-770 bound to a site at the interface between solvent and a hinge region in the CFTR protein conferred by transmembrane (tm) helices: tm4, tm5, and tm8. We re-evaluated VX-770 binding to CFTR in biological membranes using photoactivatable VX-770 probes. One such probe covalently labeled CFTR at two sites as determined following trypsin digestion and analysis by tandem-mass spectrometry. One labeled peptide resides in the cytosolic loop 4 of CFTR and the other is located in tm8, proximal to the site identified by cryo-EM. Complementary data from functional and molecular dynamic simulation studies support a model, where VX-770 mediates potentiation via multiple sites in the CFTR protein., Graphical abstract, Highlights • A photoactivatable probe of ivacaftor specifically modifies CFTR in membranes. • The probe modifies CFTR at the fourth cytosolic loop (ICL4) and at a kink formed by tm8. • Functional and molecular dynamic stimulation studies support ICL4 as a binding site., Biochemistry; Biological sciences; Biophysics; Medicine; Structural biology
- Published
- 2021