ABCMdb

ABCC7 p.Asp993Cys

None has been submitted yet.

Publications

PMID: 23709221 [PubMed] Cui G et al: "Two salt bridges differentially contribute to the maintenance of cystic fibrosis transmembrane conductance regulator (CFTR) channel function."

No. Sentence Comment

72 Open burst durations and closed durations were measured from single channel recordings of WT-, R352C-, D993C-, and R352C/D993C-CFTR, and then histograms and fits of them with single exponential functions were generated with IGOR (WaveMetrics, Inc., Lake Oswego, OR) to determine time constants for open burst durations (঄o, also called beta) and closed durations (঄c, also called ॷ) for all of the constructs. Login to comment
152 We generated R352C/D993C-CFTR and exposed the channels to MTS-2-MTS; MTS-2-MTS was chosen for this experiment because it leads to cross-linking of cysteines at a distance of b03;4.6 &#c5;, which is within the average distance for known salt bridges in a varietyofproteins(13).Priortostudieswiththedoublemutant,we also investigated each single mutant and their responses to monofunctional sulfhydryl-modifying reagents. Login to comment
162 Recovery of Charge at R352C and D993C Rescued Channel Stability in the Full Open State-R352C-CFTR exhibited single channel behavior similar to that previously reported for R352A-, R352Q-, and R352E-CFTR (13). Login to comment
176 In contrast to these results for R352C-CFTR, the stability of single channel opening in D993C-CFTR was rescued to mimic that of WT-CFTR by exposure to MTSESafa; (but not MTSEAaf9; or MTSETaf9; ), leading to significantly increased mean burst duration (supplemental Fig. 3B). Login to comment
177 Exposure to MTSESafa; also significantly decreased the conductance of the f state of D993C-CFTR (supplemental Fig. 3B). Login to comment
179 We repeated the above experiments in R352C/Cys-less V510A-CFTR and D993C/ Cys-less V510A-CFTR to further rule out the possibility of any endogenous cysteines being involved in the process. Login to comment
182 A Bifunctional MTS Reagent Can Latch R352C/D993C-CFTR into the Full Open State Even after Washout of ATP-We hypothesized that the CFTR channel pore could be latched into the open state by cross-linking the two cysteines at R352C and D993C. Login to comment
183 We first tested the effects of monofunctional reagents MTSETaf9; , MTSEAaf9; , and MTSESafa; on the double mutant R352C/D993C-CFTR. Login to comment
184 None of these reagents rescued salt Dynamic Modulation of the CFTR Pore by Salt Bridges JULY 12, 2013ߦVOLUME 288ߦNUMBER 28 JOURNAL OF BIOLOGICAL CHEMISTRY 20763 bridge function to stabilize channel behavior in R352C/D993C-CFTR in terms of stable openings to the f state (data not shown). Login to comment
185 Before applying MTS-2-MTS to the R352C/D993C-CFTR double mutant, we first tested the effects of this bifunctional linker on WT-CFTR (Fig. 6A) and Cys-less V510A-CFTR (Fig. 6B). Login to comment
187 We then examined the effects of MTS-2-MTS on R352C-D993C-CFTR (on the WT-CFTR background); a representative experiment is shown in Fig. 7. Login to comment
188 In the presence of ATP and PKA, prior to the addition of MTS-2-MTS, R352C/D993C-CFTR exhibited low open probability, unstable openings to the f state, and occasional subconductance open states. Login to comment
191 It seems likely that this reflects the fact that there are several possible consequences of exposing the double mutant to MTS-2-MTS, including covalent modification of R352C and D993C separately by two MTS-2-MTS molecules within each CFTR protein. Login to comment
209 The free energy change èc;èc;G between WT-CFTR and R352C/D993C-CFTR was afa;1.508 kcal/mol, which suggests that R352C and D993C interact with each other when CFTR is in the open state (supplemental Fig. 5). Login to comment
218 A, effects of 100 òe;M MTS-2-MTS on R352C-D993C-CFTR. Login to comment
220 B, MTS-2-MTS failed to functionally modify R352C/D993C-CFTR when applied when the channel was in the closed state. Login to comment

PMID: 25024266 [PubMed] Cui G et al: "Three charged amino acids in extracellular loop 1 are involved in maintaining the outer pore architecture of CFTR."

No. Sentence Comment

268 To further test the possible salt bridge between R104 and E116, we made use of MTS reagents that we used previously to confirm interactions between R352C and D993C (Cui et al., 2013). Login to comment
321 This is in contrast to the ability of MTS-2-MTS to lock R352C/D993C-CFTR into the open state or to lock R334C/E217C-CFTR into the closed state (Cui et al., 2013; Rahman et al., 2013). Login to comment