ABCC7 p.Lys564Cys
| Predicted by SNAP2: | A: D (66%), C: N (57%), D: D (91%), E: D (85%), F: D (85%), G: D (80%), H: D (63%), I: D (75%), L: D (75%), M: D (71%), N: D (75%), P: D (85%), Q: N (82%), R: N (93%), S: D (66%), T: D (71%), V: D (75%), W: D (91%), Y: D (80%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: D, G: N, H: N, I: D, L: D, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: D, |
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[hide] Phenylalanine-508 mediates a cytoplasmic-membrane ... Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3256-61. Epub 2008 Feb 27. Serohijos AW, Hegedus T, Aleksandrov AA, He L, Cui L, Dokholyan NV, Riordan JR
Phenylalanine-508 mediates a cytoplasmic-membrane domain contact in the CFTR 3D structure crucial to assembly and channel function.
Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3256-61. Epub 2008 Feb 27., 2008-03-04 [PMID:18305154]
Abstract [show]
Deletion of phenylalanine-508 (Phe-508) from the N-terminal nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) transporter family, disrupts both its folding and function and causes most cystic fibrosis. Most mutant nascent chains do not pass quality control in the ER, and those that do remain thermally unstable, only partially functional, and are rapidly endocytosed and degraded. Although the lack of the Phe-508 peptide backbone diminishes the NBD1 folding yield, the absence of the aromatic side chain is primarily responsible for defective CFTR assembly and channel gating. However, the site of interdomain contact by the side chain is unknown as is the high-resolution 3D structure of the complete protein. Here we present a 3D structure of CFTR, constructed by molecular modeling and supported biochemically, in which Phe-508 mediates a tertiary interaction between the surface of NBD1 and a cytoplasmic loop (CL4) in the C-terminal membrane-spanning domain (MSD2). This crucial cytoplasmic membrane interface, which is dynamically involved in regulation of channel gating, explains the known sensitivity of CFTR assembly to many disease-associated mutations in CL4 as well as NBD1 and provides a sharply focused target for small molecules to treat CF. In addition to identifying a key intramolecular site to be repaired therapeutically, our findings advance understanding of CFTR structure and function and provide a platform for focused biochemical studies of other features of this unique ABC ion channel.
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No. Sentence Comment
81 In addition to the Phe-508-containing NBD1 surface patch, residues in other regions of the domain also interact with CL4 residues as evidenced by cross-linking of Cys pairs involving amino acids closer to the Q loop (Gln-493), including W496C/T1064C and M498C/L1065C as well as nearer the Walker B motif (Asp-572) such as K564C/G1069C (Fig. 3A and SI Fig. 8).
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ABCC7 p.Lys564Cys 18305154:81:322
status: NEW97 Phe-508 participates in an apparent aromatic cluster with residues from CL4(seealsoSIFig.10).CL4alsointeractswithotherregionsinNBD1assuggested by cross-linking of residues close to the Q loop (W496C/T1064C and M498C/ L1065C) and a residue near the Walker B motif (K564C/G1069C).
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ABCC7 p.Lys564Cys 18305154:97:264
status: NEW[hide] Restoration of domain folding and interdomain asse... FASEB J. 2010 Aug;24(8):3103-12. Epub 2010 Mar 16. He L, Aleksandrov LA, Cui L, Jensen TJ, Nesbitt KL, Riordan JR
Restoration of domain folding and interdomain assembly by second-site suppressors of the DeltaF508 mutation in CFTR.
FASEB J. 2010 Aug;24(8):3103-12. Epub 2010 Mar 16., [PMID:20233947]
Abstract [show]
Deletion of PHE508 (DeltaF508) from the first nucleotide-binding domain (NBD1) of CFTR, which causes most cystic fibrosis, disrupts the folding and assembly of the protein. Although the folding pathways and yield of isolated NBD1 are altered, its global structure is not, and details of the changes in the rest of the protein remain unclear. To gain further insight into how the whole mutant protein is altered, we have determined the influence of known second-site suppressor mutations in NBD1 on the conformation of this domain and key interfaces between domains. We found that the suppressors restored maturation of only those processing mutations located in NBD1, but not in other domains, including those in the C-terminal cytoplasmic loop of the second membrane-spanning domain, which forms an interface with the NBD1 surface. Nevertheless, the suppressors promoted the formation of this interface and others in the absence of F508. The suppressors restored maturation in a DeltaF508 construct from which NBD2 was absent but to a lesser extent than in the full-length, indicating that DeltaF508 disrupts interactions involving NBD2, as well as other domains. Rescue of DeltaF508-CFTR by suppressors required the biosynthesis of the entire full-length protein in continuity, as it did not occur when N- and C-terminal "halves" were coexpressed. Simultaneous with these interdomain perturbations, DeltaF508 resulted in suppressor reversed alterations in accessibility of residues both in the F508-containing NBD1 surface loop and in the Q loop within the domain core. Thus, in the context of the full-length protein, DeltaF508 mutation causes detectable changes in NBD1 conformation, as well as interdomain interactions.
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No. Sentence Comment
123 Cys- pair cross-linking also was not observed with Cys pairs at V510C/G1069C and K564C/G1069C in the NBD1/ CL4 interface of ⌬F508-CFTR (Fig. 3B).
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ABCC7 p.Lys564Cys 20233947:123:81
status: NEW126 In addition, Cys pairs V510C/G1069C and K564C/G1069C at the NBD1/CL4 interface also were able to be cross-linked by M3M and M8M (Fig. 3B).
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ABCC7 p.Lys564Cys 20233947:126:40
status: NEW