PT  - JOURNAL ARTICLE
AU  - Rhea P Hudson
AU  - Jennifer E Dawson
AU  - P. Andrew Chong
AU  - Zhengrong Yang
AU  - Linda Millen
AU  - Philip J. Thomas
AU  - Christie G. Brouillette
AU  - Julie D. Forman-Kay
TI  - Direct Binding of the Corrector VX-809 to human CFTR NBD1: Evidence of an Allosteric Coupling between the Binding Site and the NBD1:CL4 interface
AID  - 10.1124/mol.117.108373
DP  - 2017 Jan 01
TA  - Molecular Pharmacology
PG  - mol.117.108373
4099  - http://molpharm.aspetjournals.org/content/early/2017/05/25/mol.117.108373.short
4100  - http://molpharm.aspetjournals.org/content/early/2017/05/25/mol.117.108373.full
AB  - Understanding the mechanism of action of modulator compounds for the cystic fibrosis transmembrane conductance regulator (CFTR) is key for optimization of therapeutics as well as obtaining insights into the molecular mechanisms of CFTR function. We demonstrate direct binding of VX-809 to the first nucleotide-binding domain (NBD1) of human CFTR. Disruption of the interaction between C-terminal helices and the NBD1 core upon VX-809 binding is observed from chemical shift changes in the NMR spectra of residues in the helices and on the surface of β-strands S3, S9 and S10. Binding to VX-809 leads to a significant negative shift in NBD1 thermal melting temperature (Tm), pointing to direct VX-809 interaction shifting the NBD1 conformational equilibrium. An inter-residue correlation analysis of the chemical shift changes provides evidence of allosteric coupling between the direct binding site and the NBD1:CL4 interface, thus enabling effects on the interface in the absence of direct binding in that location. These NMR binding data and the negative Tm shifts are very similar to those previously reported by us for binding of the dual corrector-potentiator CFFT-001 to NBD1 (Hudson, Chong et al. 2012), suggesting that the two compounds may share some aspects of their mechanisms of action. While previous studies have shown an important role for VX-809 in modulating the conformation of the first membrane spanning domain (MSD1) (Aleksandrov, Kota et al. 2012, Ren, Grove et al. 2013), this additional mode of VX-809 binding provides insight into conformational dynamics and allostery within CFTR.