ABCMdb

ABCC7 p.Gly1349Ala

ClinVar:	c.4046G>A , p.Gly1349Asp D , Pathogenic c.4045G>A , p.Gly1349Ser ? , not provided
CF databases:	c.4046G>A , p.Gly1349Asp D , CF-causing ; CFTR1: We tested 20 non-[delta]F508 CF chromosomes and did not find a second example of this mutation. The mutation destroys an NcoI site. c.4045G>A , p.Gly1349Ser (CFTR1) D , The mutation was found using SSCP analysis and direct sequencing. It was detected in one of the CFTR alleles of a Japanese CBAVD patient. The patient has another mutation Q1352H in the other allele.
Predicted by SNAP2:	A: D (95%), C: D (95%), D: D (66%), E: D (95%), F: D (95%), H: D (95%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), Q: D (95%), R: D (95%), S: D (95%), T: D (95%), V: D (95%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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[hide] CFTR: the nucleotide binding folds regulate the ac... J Gen Physiol. 1996 Jan;107(1):103-19. Wilkinson DJ, Mansoura MK, Watson PY, Smit LS, Collins FS, Dawson DC
CFTR: the nucleotide binding folds regulate the accessibility and stability of the activated state.
J Gen Physiol. 1996 Jan;107(1):103-19., [PMID:8741733]

Abstract [show]
The functional roles of the two nucleotide binding folds, NBF1 and NBF2, in the activation of the cystic fibrosis transmembrane conductance regulator (CFTR) were investigated by measuring the rates of activation and deactivation of CFTR Cl- conductance in Xenopus oocytes. Activation of wild-type CFTR in response to application of forskolin and 3-isobutyl-1-methylxanthine (IBMX) was described by a single exponential. Deactivation after washout of the cocktail consisted of two phases: an initial slow phase, described by a latency, and an exponential decline. Rate analysis of CFTR variants bearing analogous mutations in NBF1 and NBF2 permitted us to characterize amino acid substitutions according to their effects on the accessibility and stability of the active state. Access to the active state was very sensitive to substitutions for the invariant glycine (G551) in NBF1, where mutations to alanine (A), serine (S), or aspartic acid (D) reduced the apparent on rate by more than tenfold. The analogous substitutions in NBF2 (G1349) also reduced the on rate, by twofold to 10-fold, but substantially destabilized the active state as well, as judged by increased deactivation rates. In the putative ATP-binding pocket of either NBF, substitution of alanine, glutamine (Q), or arginine (R) for the invariant lysine (K464 or K1250) reduced the on rate similarly, by two- to fourfold. In contrast, these analogous substitutions produced opposite effects on the deactivation rate. NBF1 mutations destabilized the active state, whereas the analogous substitutions in NBF2 stabilized the active state such that activation was prolonged compared with that seen with wild-type CFTR. Substitution of asparagine (N) for a highly conserved aspartic acid (D572) in the ATP-binding pocket of NBF1 dramatically slowed the on rate and destabilized the active state. In contrast, the analogous substitution in NBF2 (D1370N) did not appreciably affect the on rate and markedly stabilized the active state. These results are consistent with a hypothesis for CFTR activation that invokes the binding and hydrolysis of ATP at NBF1 as a crucial step in activation, while at NBF2, ATP binding enhances access to the active state, but the rate of ATP hydrolysis controls the duration of the active state. The relatively slow time courses for activation and deactivation suggest that slow processes modulate ATP-dependent gating.

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150 The values listed in Table I show that NBF mutations generally reduced the value of (ko,, + ko~), in some cases by more TABLE I Summary ofActivation and DeactivationDatafor Wild-typeCFFR and Mutants of theInvariant Glycinein NBFI ((;,551)orNBF2 (G1349) CFTR Activation Deactivation klon KA (k,,n+ k,,n) (10 ~miu-1 k,,n kos latency *k,,t~ (raM) n (10-~min l) raM-l) (10-3min 1) (10 ~rain-j) n (min) (10-s min-I) wt 0.65 + 0.08 26 664 _+51 118 _+9 588 +-45 76 + 6 20 6.0 _+0.3 88 -+6 16 G551A 3.0 -+0.5*r 6 104 _+5"r 13 _+0.6*r 65 + 3*z 39 -+2* 5 7.7 +_0.5: 70 -+13: 4 G551S 4.7 +-0.5* 5 82 _+6*r 8 -+0.6*: 42 -+3*: 40 -+3*r 10 3.9 +_0.3*** 88 +-6: 6 G551D 9.3 -+0.01" 6 57 _+9*r 4 -+0.6*: 20 -+3*: 37 -+6"r 5 1.8 _+0.2"~ 84 -+10~ 6 G1349A 1.1 + 0.07*: 5 210 _+24"~ 35 -+4*: 172 -+20*: 38 +-4* 4 1.7 _+0.3"~ 184 + 20*: 5 G1349S 3.5 +-0.3* 4 199 _+46*: 23 -+5*: 117 -+27*r 82 -+19+ 6 2.3 _+0.5*+ 144 -+15": 6 G1349D 9.3 + 0.01" 8 114 _+16*++ 8 -+1": 40 +-6*r 74 -+11~ 5 0.6 -+0.1*++ 286 -+37*: 4 Valuesweredetermined as describedin Methods.The symbols(*) and (~) indicatesignificantdifferencesfrom wild-typeCFFRand the analogousmu- tant, respectively(P< 0.05). Login to comment
170 Substitutions for the invariant glycine in either NBF produced similar increases in KA, with the exception of the mutation that CFFR Activation: Roles of NBF1 and NBF2 was conservative with respect to polarity and size, alanine for glycine, which in NBF1 (G551A) produced a nearly fivefold increase in KA but in NBF2 (G1349A) produced less than a twofold increase. Login to comment
177 At the analogous site in NBF2, the most conservative substitution (G1349A) also reduced the relaxation rate, but by only about threefold. Login to comment
218 Here, even the most conservative replacement (G1349A) dramatically shortened the latency and significantly increased the rate of exponential decline. Login to comment
152 The values listed in Table I show that NBF mutations generally reduced the value of (ko,, + ko~), in some cases by more TABLE I Summary ofActivation and DeactivationDatafor Wild-typeCFFR and Mutants of theInvariant Glycinein NBFI ((;,551)orNBF2 (G1349) CFTR Activation Deactivation klon KA (k,,n+ k,,n) (10 ~miu-1 k,,n kos latency *k,,t~ (raM) n (10-~min l) raM-l) (10-3min 1) (10 ~rain-j) n (min) (10-s min-I) wt 0.65 + 0.08 26 664 _+51 118 _+9 588 +-45 76 + 6 20 6.0 _+0.3 88 -+6 16 G551A 3.0 -+0.5*r 6 104 _+5"r 13 _+0.6*r 65 + 3*z 39 -+2* 5 7.7 +_0.5: 70 -+13: 4 G551S 4.7 +-0.5* 5 82 _+6*r 8 -+0.6*: 42 -+3*: 40 -+3*r 10 3.9 +_0.3*** 88 +-6: 6 G551D 9.3 -+0.01" 6 57 _+9*r 4 -+0.6*: 20 -+3*: 37 -+6"r 5 1.8 _+0.2"~ 84 -+10~ 6 G1349A 1.1 + 0.07*: 5 210 _+24"~ 35 -+4*: 172 -+20*: 38 +-4* 4 1.7 _+0.3"~ 184 + 20*: 5 G1349S 3.5 +-0.3* 4 199 _+46*: 23 -+5*: 117 -+27*r 82 -+19+ 6 2.3 _+0.5*+ 144 -+15": 6 G1349D 9.3 + 0.01" 8 114 _+16* + + 8 -+1": 40 +-6*r 74 -+11~ 5 0.6 -+0.1* + + 286 -+37*: 4 Valuesweredetermined as describedin Methods.The symbols(*) and (~) indicatesignificantdifferencesfrom wild-typeCFFRand the analogousmu- tant, respectively(P< 0.05). Login to comment
172 Substitutions for the invariant glycine in either NBF produced similar increases in KA, with the exception of the mutation that CFFR Activation: Roles of NBF1 and NBF2 was conservative with respect to polarity and size, alanine for glycine, which in NBF1 (G551A) produced a nearly fivefold increase in KA but in NBF2 (G1349A) produced less than a twofold increase. Login to comment
179 At the analogous site in NBF2, the most conservative substitution (G1349A) also reduced the relaxation rate, but by only about threefold. Login to comment
220 Here, even the most conservative replacement (G1349A) dramatically shortened the latency and significantly increased the rate of exponential decline. Login to comment

[hide] Functional roles of the nucleotide-binding folds i... Proc Natl Acad Sci U S A. 1993 Nov 1;90(21):9963-7. Smit LS, Wilkinson DJ, Mansoura MK, Collins FS, Dawson DC
Functional roles of the nucleotide-binding folds in the activation of the cystic fibrosis transmembrane conductance regulator.
Proc Natl Acad Sci U S A. 1993 Nov 1;90(21):9963-7., [PMID:7694298]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR), a member of the traffic ATPase superfamily, possesses two putative nucleotide-binding folds (NBFs). The NBFs are sufficiently similar that sequence alignment of highly conserved regions can be used to identify analogous residues in the two domains. To determine whether this structural homology is paralleled in function, we compared the activation of chloride conductance by forskolin and 3-isobutyl-1-methylxanthine in Xenopus oocytes expressing CFTRs bearing mutations in NBF1 or NBF2. Mutation of a conserved glycine in the putative linker domain in either NBF produced virtually identical changes in the sensitivity of chloride conductance to activating conditions, and mutation of this site in both NBFs produced additive effects, suggesting that in the two NBFs this region plays a similar and critical role in the activation process. In contrast, amino acid substitutions in the Walker A and B motifs, thought to form an integral part of the nucleotide-binding pockets, produced strikingly different effects in NBF1 and NBF2. Substitutions for the conserved lysine (Walker A) or aspartate (Walker B) in NBF1 resulted in a marked decrease in sensitivity to activation, whereas the same changes in NBF2 produced an increase in sensitivity. These results are consistent with a model for the activation of CFTR in which both NBF1 and NBF2 are required for normal function but in which either the nature or the exact consequences of nucleotide binding differ for the two domains.

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60 For this reason, expression levels for easily activated constructs (wild type, G551A, G1349A, K1250Q, and D1370N) were adjusted by reducing the amount of injected RNA so that the maximum Cl- conductance was similar to that attained by less sensitive constructs. Login to comment
68 G551D, associated with severe CF (35, 36), and G1349D, also a CF mutation (37), both exhibited a dramatic reduction in sensitivity (K1l2 = 2.5 0 0 wt (12) 100 E .E CO) NBF1 A A G551A c O G551S V v G551 D NBF2 (8) A-A G1349A (9) * * G1349S (6) '-V G1349D (4) (6) (8) 0.2 0.5 1 IBMX, mM FIG. 2. Login to comment