ABCMdb

ABCC7 p.Phe1068Cys

Predicted by SNAP2:	A: D (80%), C: D (63%), D: D (95%), E: D (91%), G: D (91%), H: D (85%), I: D (85%), K: D (91%), L: D (80%), M: D (71%), N: D (85%), P: D (95%), Q: D (85%), R: D (91%), S: D (85%), T: D (91%), V: D (85%), W: D (91%), Y: N (78%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: N, Y: N,

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Publications
[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
71 Cross-linking of Cys pairs F508C/L1065C, F508C/F1068C, F508C/G1069C, and F508C/F1074C confirms that Phe-508 in NBD1 associates with CL4 in MSD2 (Fig. 3 and SI Fig. 7). Login to comment
84 Nevertheless, the proximity or relative orientation of the F508C/F1068C, F508C/G1069C, and V510C/G1069C pairs permitted very little disulfide bond formation on oxidation catalyzed by copper phenanthroline, i.e., only a very small proportion of mature band was converted to cross-linked band Fig. 2. Login to comment
131 (Bottom) Cys-less CFTR with F508C/F1068C (n ϭ 4). Login to comment