ABCC7 p.Lys464Leu
| ClinVar: |
c.1392G>T
,
p.Lys464Asn
?
, not provided
|
| Predicted by SNAP2: | A: D (95%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (95%), L: D (95%), M: D (95%), N: D (91%), 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, G: D, H: D, I: 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] Cystic fibrosis: channel, catalytic, and folding p... J Bioenerg Biomembr. 1997 Oct;29(5):429-42. Seibert FS, Loo TW, Clarke DM, Riordan JR
Cystic fibrosis: channel, catalytic, and folding properties of the CFTR protein.
J Bioenerg Biomembr. 1997 Oct;29(5):429-42., [PMID:9511928]
Abstract [show]
The identification and characterization of the CFTR gene and protein have provided not only a major impetus to the dissection of the molecular pathophysiology of cystic fibrosis (CF) but also a new perspective on the structure and function of the large superfamily of membrane transport proteins to which it belongs. While the mechanism of the active vectorial translocation of many hydrophobic substrates by several of these transporters remains nearly as perplexing as it has for several decades, considerable insight has been gained into the control of the bidirectional permeation of chloride ions through a single CFTR channel by the phosphorylation of the R-domain and ATP interactions at the two nucleotide binding domains. However, details of these catalytic and allosteric mechanisms remain to be elucidated and await the replacement of two-dimensional conceptualizations with three dimensional structure information. Secondary and tertiary structure determination is required both for the understanding of the mechanism of action of the molecule and to enable a more complete appreciation of the misfolding and misprocessing of mutant CFTR molecules. This is the primary cause of the disease in the majority of the patients and hence understanding the details of the cotranslational interactions with multiple molecular chaperones, the ubiquitin-proteasome pathway and other components of the quality control machinery at the endoplasmic reticulum could provide a basis for the development of new therapeutic interventions.
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No. Sentence Comment
101 The observed Vmax of ~30 nmol/mg/min is very low compared to other ATPases such as the Ca++ -ATPase (600 nmol/mg/min; Racker, 1985) or P-glycoprotein (300-1650 nmol/mg/min; Sharom et al., 1995), although an indication of the significance of the data is given by a negative effect due to Walker A mutations K464H and K464L.
X
ABCC7 p.Lys464Leu 9511928:101:316
status: NEW[hide] The first nucleotide binding fold of the cystic fi... J Biol Chem. 1995 Sep 22;270(38):22093-6. Ko YH, Pedersen PL
The first nucleotide binding fold of the cystic fibrosis transmembrane conductance regulator can function as an active ATPase.
J Biol Chem. 1995 Sep 22;270(38):22093-6., [PMID:7545672]
Abstract [show]
Cystic fibrosis is caused by mutations in the cell membrane protein called CFTR (cystic fibrosis transmembrane conductance regulator) which functions as a regulated Cl- channel. Although it is known that CFTR contains two nucleotide domains, both of which exhibit the capacity to bind ATP, it has not been demonstrated directly whether one or both domains can function as an active ATPase. To address this question, we have studied the first CFTR nucleotide binding fold (NBF1) in fusion with the maltose-binding protein (MBP), which both stabilizes NBF1 and enhances its solubility. Three different ATPase assays conducted on MBP-NBF1 clearly demonstrate its capacity to catalyze the hydrolysis of ATP. Significantly, the mutations K464H and K464L in the Walker A consensus motif of NBF1 markedly impair its catalytic capacity. MBP alone exhibits no ATPase activity and MBP-NBF1 fails to catalyze the release of phosphate from AMP or ADP. The Vmax of ATP hydrolysis (approximately 30 nmol/min/mg of protein) is significant and is markedly inhibited by azide and by the ATP analogs 2'-(3')-O-(2,4,6-trinitrophenyl)-adenosine-5'-triphosphate and adenosine 5'-(beta, gamma-imido)triphosphate. As inherited mutations within NBF1 account for most cases of cystic fibrosis, results reported here are fundamental to our understanding of the molecular basis of the disease.
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No. Sentence Comment
4 Significantly, the mutations K464H and K464L in the Walker A consensus motif of NBF1 markedly impair its catalytic capacity.
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ABCC7 p.Lys464Leu 7545672:4:39
status: NEW43 K464H: 5Ј-ACT GGA GCA GGC CAC ACT TCA CTT CTA-3Ј K464L: 5Ј-ACT GGA GCA GGC CTG ACT TCA CTT CTA-3Ј The identity of the two base changes was confirmed by DNA sequencing (20).
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ABCC7 p.Lys464Leu 7545672:43:61
status: NEW113 B, comparison of the purity of wild type and mutant MBP-NBF1 proteins (K464H and K464L).
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ABCC7 p.Lys464Leu 7545672:113:81
status: NEW115 C and D, the effect of the mutations K464H and K464L within NBF1 on the ATP hydrolytic activity of MBP-NBF1.
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ABCC7 p.Lys464Leu 7545672:115:47
status: NEW125 Even more convincing are results presented in Fig. 4, C and D, where it is seen that the mutations, K464H and K464L, in the Walker A nucleotide binding motif (GX4GKT) of NBF1 reduce the ATP hydrolytic capacity of purified mutant MBP-NBF1 proteins by over 80%.
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ABCC7 p.Lys464Leu 7545672:125:110
status: NEW133 The additional experimental results demonstrating that MBP alone has no catalytic capacity (Fig. 2C) and that mutations (K464H and K464L) within the Walker nucleotide binding motif GX4GKT markedly inhibit ATPase activity (Fig. 4, C and D) localize the catalytic site to NBF1.
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ABCC7 p.Lys464Leu 7545672:133:131
status: NEW42 K464H: 59-ACT GGA GCA GGC CAC ACT TCA CTT CTA-39 K464L: 59-ACT GGA GCA GGC CTG ACT TCA CTT CTA-39 The identity of the two base changes was confirmed by DNA sequencing (20).
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ABCC7 p.Lys464Leu 7545672:42:49
status: NEW112 B, comparison of the purity of wild type and mutant MBP-NBF1 proteins (K464H and K464L).
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ABCC7 p.Lys464Leu 7545672:112:81
status: NEW114 C and D, the effect of the mutations K464H and K464L within NBF1 on the ATP hydrolytic activity of MBP-NBF1.
X
ABCC7 p.Lys464Leu 7545672:114:47
status: NEW124 Even more convincing are results presented in Fig. 4, C and D, where it is seen that the mutations, K464H and K464L, in the Walker A nucleotide binding motif (GX4GKT) of NBF1 reduce the ATP hydrolytic capacity of purified mutant MBP-NBF1 proteins by over 80%.
X
ABCC7 p.Lys464Leu 7545672:124:110
status: NEW132 The additional experimental results demonstrating that MBP alone has no catalytic capacity (Fig. 2C) and that mutations (K464H and K464L) within the Walker nucleotide binding motif GX4GKT markedly inhibit ATPase activity (Fig. 4, C and D) localize the catalytic site to NBF1.
X
ABCC7 p.Lys464Leu 7545672:132:131
status: NEW