title: Binding screen for cystic fibrosis transmembrane conductance regulator correctors finds new chemical matter and yields insights into cystic fibrosis therapeutic strategy.
abstract: The most common mutation in cystic fibrosis (CF) patients is deletion of F508 (ΔF508) in the first nucleotide binding domain (NBD1) of the CF transmembrane conductance regulator (CFTR). ΔF508 causes a decrease in the trafficking of CFTR to the cell surface and reduces the thermal stability of isolated NBD1; it is well established that both of these effects can be rescued by additional revertant mutations in NBD1. The current paradigm in CF small molecule drug discovery is that, like revertant mutations, a path may exist to ΔF508 CFTR correction through a small molecule chaperone binding to NBD1. We, therefore, set out to find small molecule binders of NBD1 and test whether it is possible to develop these molecules into potent binders that increase CFTR trafficking in CF-patient-derived human bronchial epithelial cells. Several fragments were identified that bind NBD1 at either the CFFT-001 site or the BIA site. However, repeated attempts to improve the affinity of these fragments resulted in only modest gains. Although these results cannot prove that there is no possibility of finding a high-affinity small molecule binder of NBD1, they are discouraging and lead us to hypothesize that the nature of these two binding sites, and isolated NBD1 itself, may not contain the features needed to build high-affinity interactions. Future work in this area may, therefore, require constructs including other domains of CFTR in addition to NBD1, if high-affinity small molecule binding is to be achieved.
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Justin D
authors.initials: JD
authors.lastname: Hall
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Byrnes
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Suman
authors.initials: S
authors.lastname: Shanker
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Kelong
authors.initials: K
authors.lastname: Wang
authors.affiliation: Worldwide Medicinal Chemistry, , Pfizer, Cambridge, Massachusetts, 02140.
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Efremov
authors.affiliation: Molecular Structure and Function Program, Hospital for Sick Kids, Toronto, Ontario, M5G 0A4, Canada.|Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
authors.forename: P Andrew
authors.initials: PA
authors.lastname: Chong
authors.affiliation: Molecular Structure and Function Program, Hospital for Sick Kids, Toronto, Ontario, M5G 0A4, Canada.|Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
authors.forename: Julie D
authors.initials: JD
authors.lastname: Forman-Kay
authors.affiliation: Structural Biology and Biophysics Group, Pfizer, Groton, Connecticut, 06340.
authors.forename: Ann E
authors.initials: AE
authors.lastname: Aulabaugh
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D055808:Drug Discovery; D006801:Humans; D062105:Molecular Docking Simulation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D054852:Small Molecule Libraries; D019005:Cystic Fibrosis Transmembrane Conductance Regulator
keywords: CF; CFTR; NBD1; cystic fibrosis; cystic fibrosis transmembrane conductance regulator; nucleotide binding domain 1