ABCMdb

ABCC7 p.Phe446Cys

Predicted by SNAP2:	A: D (59%), C: N (61%), D: D (91%), E: D (85%), G: D (80%), H: D (80%), I: N (66%), K: D (85%), L: N (87%), M: N (72%), N: D (80%), P: D (91%), Q: D (80%), R: D (85%), S: D (71%), T: D (75%), V: N (57%), W: D (80%), Y: D (71%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: N, W: D, Y: N,

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Publications
[hide] Differences between cystic fibrosis transmembrane ... J Biol Chem. 2000 Sep 22;275(38):29407-12. Berger AL, Welsh MJ
Differences between cystic fibrosis transmembrane conductance regulator and HisP in the interaction with the adenine ring of ATP.
J Biol Chem. 2000 Sep 22;275(38):29407-12., 2000-09-22 [PMID:10893239]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is a member of the ATP-binding cassette transporter family. The most conserved features of this family are the nucleotide-binding domains. As in other members of this family, these domains bind and hydrolyze ATP; in CFTR this opens and closes the channel pore. The recent crystal structures of related bacterial transporters show that an aromatic residue interacts with the adenine ring of ATP to stabilize nucleotide binding. CFTR contains six aromatic residues that are candidates to coordinate the nucleotide base. We mutated each to cysteine and examined the functional consequences. None of the mutations disrupted channel function or the ability to discriminate between ATP, GTP, and CTP. We also applied [2-(triethylammonium)ethyl] methanethiosulfonate to covalently modify the introduced cysteines. The mutant channels CFTR-F429C, F430C, F433C, and F1232C showed no difference from wild-type CFTR, indicating that either the residues were not accessible to modification, or cysteine modification did not affect function. Although modification inactivated CFTR-Y1219C more rapidly than wild-type CFTR, and inactivation of CFTR-F446C was nucleotide-dependent; failure of these mutations to alter gating suggested that Tyr(1219) and Phe(446) were not important for nucleotide binding. The results suggest that ATP binding may not involve the coordination of the adenine ring by an aromatic residue analogous to that in some bacterial transporters. Taken together with earlier work, this study points to a model in which most of the binding energy for ATP is contributed by the phosphate groups.

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No. Sentence Comment
9 Although modification inactivated CFTR-Y1219C more rapidly than wild-type CFTR, and inactivation of CFTR-F446C was nucleotide-dependent; failure of these mutations to alter gating suggested that Tyr1219 and Phe446 were not important for nucleotide binding. Login to comment
77 When expressed in HeLa cells, CFTR-F429C, F430C, F433C, F446C, Y1219C, and F1232C all generated Cl-channel activity in excised, inside-out patches of membrane. Login to comment
126 Construct Po WT 0.29 Ϯ 0.04 F429C 0.21 Ϯ 0.03 F430C 0.30 Ϯ 0.03 F433C 0.21 Ϯ 0.03 F446C 0.34 Ϯ 0.06 Y1219C 0.26 Ϯ 0.07 F1232C 0.35 Ϯ 0.02 FIG. 2. Login to comment
142 CFTR variant k M -1 s-1 Wild-type 23.1 Ϯ 6.4 F429C 27.0 Ϯ 16.7 F430C 34.6 Ϯ 22.8 F433C 19.0 Ϯ 5.5 F446C 36.1 Ϯ 15.8 Y1219C 75.5 Ϯ 20.1* F1232C 68.5 Ϯ 19.6 not interfere with the ability of MTSET to inactivate CFTR-Y1219C. Login to comment
151 In contrast to the other channels, CFTR-F446C showed a more striking inhibition by MTSET in the absence than in the presence of ATP (compare Fig. 4, A and B, with Fig. 3) that was not explained by the rate of inhibition observed in the presence of ATP (Table II). Login to comment
155 Reaction of CFTR-F446C with MTSET for 60 s in the presence of 1 mM ADP preserved almost all CFTR activity (Fig. 6). Login to comment
191 CFTR-F446C was the only channel in which nucleotide altered the inactivation rate. Login to comment