ABCC7 p.Lys335His
| Predicted by SNAP2: | A: D (66%), C: D (80%), D: D (91%), E: D (75%), F: D (91%), G: D (80%), H: D (80%), I: D (80%), L: D (80%), M: D (80%), N: D (80%), P: D (91%), Q: N (53%), R: N (87%), S: D (66%), T: D (75%), V: D (80%), W: D (91%), Y: D (85%), |
| Predicted by PROVEAN: | A: N, C: D, D: N, E: N, F: D, G: N, H: N, I: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: D, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] Cystic fibrosis transmembrane conductance regulato... Biophys J. 1998 Mar;74(3):1320-32. Mansoura MK, Smith SS, Choi AD, Richards NW, Strong TV, Drumm ML, Collins FS, Dawson DC
Cystic fibrosis transmembrane conductance regulator (CFTR) anion binding as a probe of the pore.
Biophys J. 1998 Mar;74(3):1320-32., [PMID:9512029]
Abstract [show]
We compared the effects of mutations in transmembrane segments (TMs) TM1, TM5, and TM6 on the conduction and activation properties of the cystic fibrosis transmembrane conductance regulator (CFTR) to determine which functional property was most sensitive to mutations and, thereby, to develop a criterion for measuring the importance of a particular residue or TM for anion conduction or activation. Anion substitution studies provided strong evidence for the binding of permeant anions in the pore. Anion binding was highly sensitive to point mutations in TM5 and TM6. Permeability ratios, in contrast, were relatively unaffected by the same mutations, so that anion binding emerged as the conduction property most sensitive to structural changes in CFTR. The relative insensitivity of permeability ratios to CFTR mutations was in accord with the notion that anion-water interactions are important determinants of permeability selectivity. By the criterion of anion binding, TM5 and TM6 were judged to be likely to contribute to the structure of the anion-selective pore, whereas TM1 was judged to be less important. Mutations in TM5 and TM6 also dramatically reduced the sensitivity of CFTR to activation by 3-isobutyl 1-methyl xanthine (IBMX), as expected if these TMs are intimately involved in the physical process that opens and closes the channel.
Comments [show]
None has been submitted yet.
No. Sentence Comment
229 Hipper et al. (1995) reported that the mutations R334E, R334H, K335E, K335H, R347E, and R347H did not alter CFTR conduction properties, but careful inspection of the data presented revealed that the level of CFTR expression was very low so that altered properties of mutant CFTRs might have been easily obscured.
X
ABCC7 p.Lys335His 9512029:229:70
status: NEW[hide] Mutations in the putative pore-forming domain of C... FEBS Lett. 1995 Nov 6;374(3):312-6. Hipper A, Mall M, Greger R, Kunzelmann K
Mutations in the putative pore-forming domain of CFTR do not change anion selectivity of the cAMP activated Cl- conductance.
FEBS Lett. 1995 Nov 6;374(3):312-6., [PMID:7589561]
Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) apparently forms Cl- channels in apical membranes of secretory epithelial cells. A detailed model describes molecular structure and biophysical properties of CFTR and the impact of various mutations as they occur in cystic fibrosis. In the present report mutations were introduced into the putative 6th alpha-helical transmembrane pore forming domain of CFTR. The mutants were subsequently expressed in Xenopus oocytes by injection of the respective cRNAs. Whole cell (wc) conductances could be reversibly activated by IBMX (1 nmol/l) only in oocytes injected with wild-type (wt) or mutant CFTR but not in oocytes injected with water or antisense CFTR. The activated conductance was partially inhibited by (each 100 mumol/l) DIDS (27%) and glibenclamide (77%), but not by 10 mumol/l NPPB. The following mutations were examined: K335E, R347E, R334E, K335H, R347H, R334H. They did not measurably change the wt-CFTR anion permeability (P) and we conductance (G) sequence of: PCl- > PBr- > P1- and GCl- > GBr- > G1-, respectively. Moreover, anomalous mole fraction behavior for the cAMP activated current could not be detected: neither in wt-CFTR nor in R347E-CFTR. Various mutants for which positively charged amino acids were replaced by histidines (K335H, R347H, R334H) did not show pH sensitivity of the IBMX activated wc conductance. We, therefore, cannot confirm previous results. CFTR might have a different molecular structure than previously suggested or it might act as a regulator of ion conductances.
Comments [show]
None has been submitted yet.
No. Sentence Comment
6 The following mutations were examined: K335E, R347E, R334E, K335H, R347H, R334H.
X
ABCC7 p.Lys335His 7589561:6:60
status: NEW9 Various mutants for which positively charged amino acids were replaced by histidines (K335H, R347H, R334H) did not show pH sensitivity of the IBMX activated wc conductance.
X
ABCC7 p.Lys335His 7589561:9:86
status: NEW32 Synthesis of mutated CFTR-cDNA was induced by annealing of ampicillin repair oligonucleotide and oligonucleotide primers carrying the respective mutation changing positively charged to negatively charged amino acids (R334E, R347E, K335E) or replacing R and K at these positions by histidines (R334H, R347H, K335H).
X
ABCC7 p.Lys335His 7589561:32:307
status: NEW76 I R334EIIR334HI K335E...... I K335H I R347EII R347H l (n=16) n=10) (n=10) (n=24) (n=9) "° ,11 ml I'lnt;"i' ii Illll 111 0.8 X T °., I ~ 0.4 0.2 I o.o ~ ~ ~ 6!~ 6 ~ 8 ~ ,I I ~ ...... ] J I I L ...... ,j I I t 1 I * *J t........ ~,_J L * * I * *I _ J I .......... I I , * * * , (n=18) (n=lO) (n=22) (n=7) 1.o - T T (n=8) (n=14) T / T T T o.eT T T o 1 "~ 0.4-O 0.2- oo_ L__J , i I i t - - I 1 I I I ~ t J L ' t * J I__~ * I [ * * I l * * j l.
X
ABCC7 p.Lys335His 7589561:76:30
status: NEW80 Next, positively charged amino acids R334, R347, K335 located in the putative 6th pore forming transmembrane a-helical domain of CFTR, were exchanged by histidines (R334H, R347H, K335H) or by the negatively charged glutamate (R334E, R347E, K335E).
X
ABCC7 p.Lys335His 7589561:80:179
status: NEW81 Wc conductances were activated significantly by IBMX in all 6 mutants but to variable degrees (AG in/.tS): 3.2 + 0.6 (R334E, n = 20), 2.7 + 0.6 (R334H, n = 13), 7.1 + 0.9 (K335E, n-- 20), 2.8 + 0.7 (K335H, n = 10), 3.2 + 0.04 (R347E, n = 32) and 1.8 + 0.3 (R347H, n = 10).
X
ABCC7 p.Lys335His 7589561:81:199
status: NEW91 Following previous experiments [7] wc C1- conductances were examined in mutants bearing a histidine mutation (K335H, R347H, R334H) at different extracellular pH values.
X
ABCC7 p.Lys335His 7589561:91:110
status: NEW94 aL IFEBS Letters 374 (1995) 312-316 - ~ - K335H (n=7) .... ~ .... R347H (n=8) 8 - • R334H (n=5) ...6- I~ ...L 25.5/6 7.5 8/8.5 opH Fig. 5. Summary of the conductances obtained from IBMX stimulated oocytes at different extracellular pH values.
X
ABCC7 p.Lys335His 7589561:94:43
status: NEW95 Experiments were performed with oocytes overexpressing three different CFTR mutants: K335H, R347H, R334H.
X
ABCC7 p.Lys335His 7589561:95:85
status: NEW108 In the present study we repeated some of the published (K335E, R347E, R347H) and performed additional mutations (R334E, R334H, K335H) which are all located in the putative sixth transmembrane domain and overexpressed the respective CFTRs in oocytes.
X
ABCC7 p.Lys335His 7589561:108:127
status: NEW117 Additional mutations were constructed in which positively charged lysine and two arginines in the sixth transmembrane domain were replaced by pH-sensitive histidines (R334H, K335H, R347H).
X
ABCC7 p.Lys335His 7589561:117:174
status: NEW