ABCC7 p.Phe337Leu

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PMID: 26606940 [PubMed] Wei S et al: "Long-range coupling between the extracellular gates and the intracellular ATP binding domains of multidrug resistance protein pumps and cystic fibrosis transmembrane conductance regulator channels."
No. Sentence Comment
70 Primer sequences for cloning and site-directed mutagenesis Ycf1p Forward cloning primer: CAACACAGGCATGTATATTA- AGAGC Reverse cloning primer: TTAAACTTATGGCGTCAGAG- TTGCC F565A: CATTGACTACTGACTTAGTTGCCCCTGCTTTG- ACTCTGTTC F565S: CATTGACTACTGACTTAGTTTCCCCTGCTTTGA- CTCTGTTC F565L: CATTGACTACTGACTTAGTTTTACCTGCTTTG- ACTCTGTTC G756D: AAGACAAACGAGCTTTTTGATCTCCAGATAAG- GAGATCCC D777N: ACAGCTGGCAAAGGATCATTAAGTAAATAAG- TGTCAGCTC Y1281G: GATCAAGCTCCGGCCTACCACGAGTGGAATA- ATTATTAAAC Yor1p Forward cloning primer: CTAATTGTACATCCGGTTTT- AACC Reverse cloning primer: TTGAGTCATTGCCCTTAA- AATGG F468S: AGGCAACCTGGTAATATTTCTGCCTCTTTATC- TTTATTTC F468A: AGGCAACCTGGTAATATTGCTGCCTCTTTATC- TTTATTTC F468L: AGGCAACCTGGTAATATTCTTGCCTCTTTATC- TTTATTTC G713D: GTGGTATTACTTTATCTGGTGATCAAAAGGCA- CGTATCAATTT Y1222G: ATAGGTAAACCAGGTCTACCGGCAAAATCAA- CATTTTCAA CFTR Forward cloning primer: GAAGAAGCAATGGAAAAA- ATGATTG Reverse cloning primer: TCGGTGAATGTTCTGACCT- TGG F337S: TCATCCTCCGGAAAATATCCACCACCATCTCA- TTCTGC F337A: TCATCCTCCGGAAAATAGCCACCACCATCTCA- TTCTGC F337L: TCATCCTCCGGAAAATATTAACCACCATCTCA- TTCTGC F337C: TCATCCTCCGGAAAATATGCACCACCATCTC- ATTCTGC Immunoblot analysis of CFTR protein expression Expression of the CFTR F337 mutants was verified by immunoblotting as described elsewhere (15).
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ABCC7 p.Phe337Leu 26606940:70:1037
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148 B) Macroscopic current record for excised patch containing approximately the same number of F337L- CFTR channels showing that this mutation does not increase ATP-free channel activity or subsequent activation by AMP-PNP.
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ABCC7 p.Phe337Leu 26606940:148:92
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152 Mean percent ATP-free currents 6 SEMs were as follows: WT (0.5 6 0.2%; n = 5); F337L (0.6 6 0.3%; n = 5); F337C (2.5 6 1.4%; n = 5), F337A (9.6 6 1.4%; n = 5), and F337S (15.8 6 4.5%; n = 10).
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ABCC7 p.Phe337Leu 26606940:152:79
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162 The results in Fig. 5 confirm that the extracellular F337S mutation increased Po especially following ATP removal and the subsequent addition of AMP-PNP.
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ABCC7 p.Phe337Leu 26606940:162:41
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163 Interestingly, the leucine substitution (F337L), which was a strong GOF mutation in Ycf1p but a weaker GOF mutation in Yor1p, had no detectable GOF effect on CFTR channel activity (Fig. 4B-D).
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ABCC7 p.Phe337Leu 26606940:163:41
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308 The F337L mutation did not obviously disrupt CFTR protein maturation or inhibit the control ATP-dependent currents in macropatches (Fig. 4).
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ABCC7 p.Phe337Leu 26606940:308:4
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69 Primer sequences for cloning and site-directed mutagenesis Ycf1p Forward cloning primer: CAACACAGGCATGTATATTA- AGAGC Reverse cloning primer: TTAAACTTATGGCGTCAGAG- TTGCC F565A: CATTGACTACTGACTTAGTTGCCCCTGCTTTG- ACTCTGTTC F565S: CATTGACTACTGACTTAGTTTCCCCTGCTTTGA- CTCTGTTC F565L: CATTGACTACTGACTTAGTTTTACCTGCTTTG- ACTCTGTTC G756D: AAGACAAACGAGCTTTTTGATCTCCAGATAAG- GAGATCCC D777N: ACAGCTGGCAAAGGATCATTAAGTAAATAAG- TGTCAGCTC Y1281G: GATCAAGCTCCGGCCTACCACGAGTGGAATA- ATTATTAAAC Yor1p Forward cloning primer: CTAATTGTACATCCGGTTTT- AACC Reverse cloning primer: TTGAGTCATTGCCCTTAA- AATGG F468S: AGGCAACCTGGTAATATTTCTGCCTCTTTATC- TTTATTTC F468A: AGGCAACCTGGTAATATTGCTGCCTCTTTATC- TTTATTTC F468L: AGGCAACCTGGTAATATTCTTGCCTCTTTATC- TTTATTTC G713D: GTGGTATTACTTTATCTGGTGATCAAAAGGCA- CGTATCAATTT Y1222G: ATAGGTAAACCAGGTCTACCGGCAAAATCAA- CATTTTCAA CFTR Forward cloning primer: GAAGAAGCAATGGAAAAA- ATGATTG Reverse cloning primer: TCGGTGAATGTTCTGACCT- TGG F337S: TCATCCTCCGGAAAATATCCACCACCATCTCA- TTCTGC F337A: TCATCCTCCGGAAAATAGCCACCACCATCTCA- TTCTGC F337L: TCATCCTCCGGAAAATATTAACCACCATCTCA- TTCTGC F337C: TCATCCTCCGGAAAATATGCACCACCATCTC- ATTCTGC Immunoblot analysis of CFTR protein expression Expression of the CFTR F337 mutants was verified by immunoblotting as described elsewhere (15).
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ABCC7 p.Phe337Leu 26606940:69:1037
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147 B) Macroscopic current record for excised patch containing approximately the same number of F337L- CFTR channels showing that this mutation does not increase ATP-free channel activity or subsequent activation by AMP-PNP.
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ABCC7 p.Phe337Leu 26606940:147:92
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151 Mean percent ATP-free currents 6 SEMs were as follows: WT (0.5 6 0.2%; n = 5); F337L (0.6 6 0.3%; n = 5); F337C (2.5 6 1.4%; n = 5), F337A (9.6 6 1.4%; n = 5), and F337S (15.8 6 4.5%; n = 10).
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ABCC7 p.Phe337Leu 26606940:151:79
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307 The F337L mutation did not obviously disrupt CFTR protein maturation or inhibit the control ATP-dependent currents in macropatches (Fig. 4).
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ABCC7 p.Phe337Leu 26606940:307:4
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PMID: 10827976 [PubMed] Linsdell P et al: "Molecular determinants of anion selectivity in the cystic fibrosis transmembrane conductance regulator chloride channel pore."
No. Sentence Comment
70 The mutants F337L, F337Y, and I344A gave only modest alterations in anion permeability (Table 1) that led to only slight changes in the anion selectivity sequence (Table 2).
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ABCC7 p.Phe337Leu 10827976:70:12
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77 Both wild-type and F337Y (Fig. 3), as well as F337L, F337W, and I344A (not shown; see Table 2), were able to select for anions that bound water molecules less strongly, consistent with the lyotropic selectivity sequence common to most classes of Clafa; channels (see Introduction).
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ABCC7 p.Phe337Leu 10827976:77:46
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116 Although we cannot rule out this possibility, we feel that the fact that mutations at two adjacent TM6 residues, F337 (this study) and T338 (Linsdell et al., 1998), significantly affect TABLE 1 Relative permeability of intracellular ions in wild-type and mutant CFTR Cld1a; channels Wild type F337A F337S F337L F337Y F337W I344A Cl 1.00 afe; 0.01 (10) 1.00 afe; 0.04 (6) 1.00 afe; 0.08 (3) 1.00 afe; 0.02 (5) 1.00 afe; 0.02 (6) 1.00 afe; 0.03 (5) 1.00 afe; 0.01 (9) Br 1.37 afe; 0.07 (8) 0.60 afe; 0.04 (4)** 0.50 afe; 0.04 (4)** 1.22 afe; 0.04 (5) 1.39 afe; 0.04 (3) 1.12 afe; 0.05 (4)* 1.74 afe; 0.01 (3)* I 0.83 afe; 0.03 (6) 0.23 afe; 0.04 (5)** 0.23 afe; 0.02 (4)** 0.39 afe; 0.01 (3)** 0.69 afe; 0.03 (7)* - 0.99 afe; 0.05 (4)* F 0.103 afe; 0.007 (9) 0.35 afe; 0.01 (4)** 0.43 afe; 0.02 (4)** 0.15 afe; 0.02 (3)* 0.095 afe; 0.009 (3) 0.081 afe; 0.009 (3) 0.075 afe; 0.012 (5)* SCN 3.55 afe; 0.26 (7) 0.97 afe; 0.05 (4)** 0.93 afe; 0.10 (5)** 2.85 afe; 0.20 (4) 3.05 afe; 0.29 (4) 4.42 afe; 0.56 (4) 3.27 afe; 0.30 (5) NO3 1.58 afe; 0.04 (10) 1.30 afe; 0.03 (3)* 1.08 afe; 0.02 (4)** 1.38 afe; 0.03 (4)* 1.43 afe; 0.04 (3) 1.62 afe; 0.03 (3) 1.71 afe; 0.06 (4) ClO4 0.25 afe; 0.01 (8) 0.19 afe; 0.00 (3)* 0.17 afe; 0.03 (4)* 0.23 afe; 0.04 (3) 0.15 afe; 0.01 (4)** - 0.24 afe; 0.02 (3) Formate 0.24 afe; 0.01 (9) 0.27 afe; 0.02 (3) 0.33 afe; 0.03 (4)* 0.35 afe; 0.02 (3)* 0.24 afe; 0.01 (3) - 0.28 afe; 0.01 (3) Acetate 0.091 afe; 0.003 (10) 0.073 afe; 0.004 (3)* 0.12 afe; 0.02 (5) - 0.092 afe; 0.014 (4) - 0.076 afe; 0.007 (3) Naaf9; 0.007 afe; 0.010 (24) 0.001 afe; 0.018 (3) 0.001 afe; 0.021 (5) - 0.002 afe; 0.004 (3) - - Relative permeabilities for different anions present in the intracellular solution under biionic conditions were calculated from macroscopic current reversal potentials (e.g., Fig. 2), according to Eq. 1 (see Materials and Methods).
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ABCC7 p.Phe337Leu 10827976:116:308
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122 TABLE 2 Anion selectivity sequences for wild-type and mutant CFTR Cld1a; channels Wild-type SCNafa; b0e; NO3 afa; b0e; Brafa; b0e; Clafa; b0e; Iafa; b0e; ClO4 afa; b07; form b0e; Fafa; b0e; ace F337A NO3 afa; b0e; Clafa; c56; SCNafa; b0e; Brafa; b0e; Fafa; b0e; form c56; Iafa; b0e; ClO4 afa; b0e; ace F337S NO3 afa; b0e; Clafa; c56; SCNafa; b0e; Brafa; b0e; Fafa; b0e; form b0e; Iafa; b0e; ClO4 afa; b0e; ace F337L SCNafa; b0e; NO3 afa; b0e; Brafa; b0e; Clafa; b0e; Iafa; b0e; form b0e; ClO4 afa; b0e; Fafa; F337Y SCNafa; b0e; NO3 afa; c56; Brafa; b0e; Clafa; b0e; Iafa; b0e; form b0e; ClO4 afa; b0e; Fafa; b07; ace I344A SCNafa; b0e; Brafa; c56; NO3 afa; b0e; Clafa; b07; Iafa; b0e; form b0e; ClO4 afa; b0e; ace b07; Fafa; Sequences were derived from the relative anion permeabilities given in Table 1. form, formate; ace, acetate.
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ABCC7 p.Phe337Leu 10827976:122:548
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158 While the mutants F337L, F337Y, and I344A maintain Eisenman sequence III, both F337A and F337S convert the channel to a relatively strong field strength sequence (Clafa; b0e; Brafa; b0e; Fafa; b0e; Iafa; ; Eisenman sequence V) (Table 2).
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ABCC7 p.Phe337Leu 10827976:158:18
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168 Thus in wild-type CFTR (and to a similar extent F337L and F337Y), the bulky side chain at position 337 might impede the approach of permeating anions to a nearby anion-attracting group, ensuring relatively weak, long-distance interactions between the anion and this positive site.
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ABCC7 p.Phe337Leu 10827976:168:48
status: NEW
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