ABCC7 p.Val1129Cys

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PMID: 19381710 [PubMed] Fatehi M et al: "Novel residues lining the CFTR chloride channel pore identified by functional modification of introduced cysteines."
No. Sentence Comment
71 As described previously for modification of cysteines introduced into TM6 (Fatehi and Linsdell 2008) and the extracellular loop between TMs 1 and 2 (Zhou et al. 2008), MTSET and MTSES altered the IREL-V shape in S1118C, T1121C, T1122C, G1127C, V1129C, I1131C and I1132C.
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ABCC7 p.Val1129Cys 19381710:71:244
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72 Of 21 cysteine mutants studied, only six significantly altered I-V relationship shape in the absence of external MTS reagents (Fig. 3a), with S1118C, T1121C, T1122C, G1127C and A1136C all causing significant inward rectification and V1129C showing outward rectification.
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ABCC7 p.Val1129Cys 19381710:72:233
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83 Only one mutant-V1129C-significantly affected the magnitude of unitary currents at hyperpolarized voltages (Figs. 4, 5a), giving a decrease in unitary current amplitude of *12% at -80 mV (Fig. 5a).
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ABCC7 p.Val1129Cys 19381710:83:16
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84 Unitary currents at depolarized voltages were significantly decreased in S1118C, T1121C, T1122C and G1127C and significantly increased in V1129C (Fig. 5b).
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ABCC7 p.Val1129Cys 19381710:84:138
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85 This resulted in changes in the shape of the i-V relationship, causing inward rectification in the case of S1118C, T1121C, T1122C and G1127C and outward rectification in the case of V1129C (Figs. 4b, 5c).
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ABCC7 p.Val1129Cys 19381710:85:182
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91 Indeed, changes in unitary current amplitude were observed in S1118C, T1121C, T1122C, G1127C, V1129C, I1131C and I1132C, but not wild-type, when MTS reagents were included in the pipette solution (Fig. 6).
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ABCC7 p.Val1129Cys 19381710:91:96
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119 In contrast, the other three mutations (V1129C, I1131C, I1132C) led to no change or even a slight increase in unitary current amplitude (Fig. 5b) and more minor effects of MTS modification, resulting in no change or a small decrease in amplitude with MTSES and increases in amplitude to levels above wild-type with MTSET (Fig. 9b).
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ABCC7 p.Val1129Cys 19381710:119:40
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124 Under these conditions, SCN- block was significantly strengthened in I1132C (at hyperpolarized and depolarized voltages), S1118C (at hyperpolarized voltages), T1121C and V1129C (at depolarized voltages) and I1131C (at very depolarized voltages only) Fig. 4 Single-channel currents carried by cysteine mutant forms of CFTR.
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ABCC7 p.Val1129Cys 19381710:124:170
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125 a Example single-channel currents carried by wild-type, S1118C, T1121C, T1122C and V1129C, at membrane potentials of ?60 (top) and -60 (bottom) mV.
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ABCC7 p.Val1129Cys 19381710:125:83
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133 Under these conditions, SCN- permeability was significantly increased in S1118C and (to a lesser extent) T1122C and G1127C and unaltered in T1121C, V1129C, I1131C and I1132C (Fig. 11).
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ABCC7 p.Val1129Cys 19381710:133:148
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158 Of the seven mutants that were functionally modified by MTS reagents, five (S1118C, T1121C, T1122C, G1127C, V1129C) also showed significantly altered unitary current amplitude in the absence of MTS modification (Figs. 4, 5).
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ABCC7 p.Val1129Cys 19381710:158:108
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161 a S1118C (d), T1121C (j), T1122C (), G1127C (h); b V1129C (m), I1131C (r), I1132C (.).
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ABCC7 p.Val1129Cys 19381710:161:52
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183 We speculate that one group of reactive mutants (S1118C, T1121C, T1122C, G1127C) is located relatively deep in the pore from the outside and that the other (V1129C, Fig. 11 Thiocyanate permeability of mutants.
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ABCC7 p.Val1129Cys 19381710:183:157
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191 Chloride conductance was further reduced by MTSES modification at these sites, indicating the detrimental effect of depositing a negative charge within the permeation pathway. Cysteine substitution at the outer mouth of the pore (V1129C, I1131C, I1132C) (Fig. 9b) had somewhat different effects.
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ABCC7 p.Val1129Cys 19381710:191:230
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