TY - JOUR
T1 - Direct binding of the Corrector VX-809 to Human CFTR NBD1
T2 - Evidence of an Allosteric coupling between the Binding site and the NBD1:CL4 Interface s
AU - Hudson, Rhea P.
AU - Dawson, Jennifer E.
AU - Chong, P. Andrew
AU - Yang, Zhengrong
AU - Millen, Linda
AU - Thomas, Philip J.
AU - Brouillette, Christie G.
AU - Forman-Kay, Julie D.
N1 - Funding Information:
This work was funded by Cystic Fibrosis Foundation Therapeutics [Grants FORMAN13XX0, BROUIL08XX0, and BROUIL13XX0]; and Cystic Fibrosis Canada [Grant 3175]. The authors thank Drs. Ranjith Muhandiram, Lewis E. Kay, and Scott Prosser for assistance with NMR experiments; and Dr. Algirdas Velyvis for the scripts to calculate global fit Kd values from chemical shift changes. The authors also thank Frederick Van Goor, Vertex Pharmaceuticals, Inc., for VRT-528, the initial supply of VX-809, and stimulating discussions. In addition, thanks to J. Spencer Emtage, Hal A. Lewis, Shane Atwell, and the entire SGX Pharmaceuticals, Inc. (San Diego, CA) CFTR team for providing the unpublished crystal coordinate data for the BIA complex with NBD1.
Publisher Copyright:
Copyright © 2017 by The Author(s)
PY - 2017/8
Y1 - 2017/8
N2 - Understanding the mechanism of action of modulator compounds for the cystic fibrosis transmembrane conductance regulator (CFTR) is key for the optimization of therapeutics as well as obtaining insights into the molecular mechanisms of CFTR function. We demonstrate the 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 b-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 et al., 2012), suggesting that the two compounds may share some aspects of their mechanisms of action. Although previous studies have shown an important role for VX-809 in modulating the conformation of the first membrane spanning domain (Aleksandrov et al., 2012; Ren et al., 2013), this additional mode of VX-809 binding provides insight into conformational dynamics and allostery within CFTR.
AB - Understanding the mechanism of action of modulator compounds for the cystic fibrosis transmembrane conductance regulator (CFTR) is key for the optimization of therapeutics as well as obtaining insights into the molecular mechanisms of CFTR function. We demonstrate the 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 b-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 et al., 2012), suggesting that the two compounds may share some aspects of their mechanisms of action. Although previous studies have shown an important role for VX-809 in modulating the conformation of the first membrane spanning domain (Aleksandrov et al., 2012; Ren et al., 2013), this additional mode of VX-809 binding provides insight into conformational dynamics and allostery within CFTR.
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U2 - 10.1124/mol.117.108373
DO - 10.1124/mol.117.108373
M3 - Article
C2 - 28546419
AN - SCOPUS:85024093558
SN - 0026-895X
VL - 92
SP - 124
EP - 135
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 2
ER -