title: Solubilizing mutations used to crystallize one CFTR domain attenuate the trafficking and channel defects caused by the major cystic fibrosis mutation.
abstract: Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) Cl(-) channel. F508del, the most frequent CF-causing mutation, disrupts both the processing and function of CFTR. Recently, the crystal structure of the first nucleotide-binding domain of CFTR bearing F508del (F508del-NBD1) was elucidated. Although F508del-NBD1 shows only minor conformational changes relative to that of wild-type NBD1, additional mutations (F494N/Q637R or F429S/F494N/Q637R) were required for domain solubility and crystallization. Here we show that these solubilizing mutations in cis with F508del partially rescue the trafficking defect of full-length F508del-CFTR and attenuate its gating defect. We interpret these data to suggest that the solubilizing mutations utilized to facilitate F508del-NBD1 production also assist folding of full-length F508del-CFTR protein. Thus, the available crystal structure of F508del-NBD1 might correspond to a partially corrected conformation of this domain.
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisboa, 1749-016 Lisboa, Portugal.
authors.forename: Luísa S
authors.initials: LS
authors.lastname: Pissarra
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Farinha
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.forename: André
authors.initials: A
authors.lastname: Schmidt
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Thibodeau
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Cai
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Thomas
authors.forename: David N
authors.initials: DN
authors.lastname: Sheppard
authors.forename: Margarida D
authors.initials: MD
authors.lastname: Amaral
mesh_terms: D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D003550:Cystic Fibrosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009711:Nucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D012995:Solubility; D013237:Stereoisomerism; D013997:Time Factors
chemical_list: D009711:Nucleotides; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator