ABCC8 p.Trp232Ala
| Predicted by SNAP2: | A: D (85%), C: D (75%), D: D (95%), E: D (91%), F: D (80%), G: D (91%), H: D (91%), I: D (91%), K: D (95%), L: D (91%), M: D (91%), N: D (91%), P: D (95%), Q: D (91%), R: D (95%), S: D (91%), T: D (91%), V: D (85%), Y: D (75%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: 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, Y: D, |
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[hide] Toward linking structure with function in ATP-sens... Diabetes. 2004 Dec;53 Suppl 3:S104-12. Bryan J, Vila-Carriles WH, Zhao G, Babenko AP, Aguilar-Bryan L
Toward linking structure with function in ATP-sensitive K+ channels.
Diabetes. 2004 Dec;53 Suppl 3:S104-12., [PMID:15561897]
Abstract [show]
Advances in understanding the overall structural features of inward rectifiers and ATP-binding cassette (ABC) transporters are providing novel insight into the architecture of ATP-sensitive K+ channels (KATP channels) (KIR6.0/SUR)4. The structure of the K(IR) pore has been modeled on bacterial K+ channels, while the lipid-A exporter, MsbA, provides a template for the MDR-like core of sulfonylurea receptor (SUR)-1. TMD0, an NH2-terminal bundle of five alpha-helices found in SURs, binds to and activates KIR6.0. The adjacent cytoplasmic L0 linker serves a dual function, acting as a tether to link the MDR-like core to the KIR6.2/TMD0 complex and exerting bidirectional control over channel gating via interactions with the NH2-terminus of the KIR. Homology modeling of the SUR1 core offers the possibility of defining the glibenclamide/sulfonylurea binding pocket. Consistent with 30-year-old studies on the pharmacology of hypoglycemic agents, the pocket is bipartite. Elements of the COOH-terminal half of the core recognize a hydrophobic group in glibenclamide, adjacent to the sulfonylurea moiety, to provide selectivity for SUR1, while the benzamido group appears to be in proximity to L0 and the KIR NH2-terminus.
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No. Sentence Comment
146 Substitution of Trp232 with alanine results in loss of affinity labeling, whereas replacement with cysteine retains labeling.
X
ABCC8 p.Trp232Ala 15561897:146:16
status: NEW162 Results for the wild-type (WT) control, the Tyr230Ala (Y230A), and Trp231Ala (W232A) substitutions are shown.
X
ABCC8 p.Trp232Ala 15561897:162:78
status: NEW[hide] Defining a binding pocket for sulfonylureas in ATP... FASEB J. 2007 Jan;21(1):18-25. Epub 2006 Nov 16. Vila-Carriles WH, Zhao G, Bryan J
Defining a binding pocket for sulfonylureas in ATP-sensitive potassium channels.
FASEB J. 2007 Jan;21(1):18-25. Epub 2006 Nov 16., [PMID:17110465]
Abstract [show]
Sulfonylurea receptors SUR1 and SUR2 are the regulatory subunits of K(ATP) channels. Their differential affinity for hypoglycemic sulfonylureas provides a basis for the selectivity of these compounds for different K(ATP) channel isoforms. Sulfonylureas have a 100- to 1000-fold greater affinity for SUR1 vs. SUR2. Structure-activity studies suggested a bipartite binding pocket. Chimeric SUR1 approximately SUR2 receptors have shown TMD2, the third bundle of transmembrane helices, to be part of an "A" site that confers SUR1 selectivity for sulfonylureas. The purpose of this study is to determine the position of the "B" site. Previous photoaffinity labeling studies have placed the B site on the amino-terminal third of SUR and colabeled the associated K(IR). In our study, deletion of TMD0, the first bundle of transmembrane helices, did not compromise labeling. Further deletions into the cytoplasmic linker, L0, eliminated binding and labeling. Alanine substitutions in L0 identified a limited number of conserved residues, Y230 and W232, important for affinity labeling. A fragment of K(IR)6.2, missing M2 and the entire carboxyl terminal, assembles with SUR1 and is affinity labeled, while deletion of 10 or more amino-terminal residues compromises labeling. These studies indicate that the B site involves L0 and the K(IR) amino terminus, elements that are critical for control of channel gating.
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No. Sentence Comment
104 The graph shows a decrease in photoaffinity labeling for SUR1 Y230A and W232A (Fig. 3C).
X
ABCC8 p.Trp232Ala 17110465:104:72
status: NEW126 The data are plotted as the ratio of label-toprotein in arbitrary units Ϯ sd. the SUR1, Y230A, and W232A substitutions.
X
ABCC8 p.Trp232Ala 17110465:126:106
status: NEWX
ABCC8 p.Trp232Ala 17110465:126:109
status: NEW127 Both SUR1 and KIR6.2 in KATP channels are affinity-labeled by [125 I]-azido-glibenclamide and coexpression of SUR1, Y230A, and W232A with KIR6.2 resulted in labeling of the KIR (data not shown) and also in an increase of the mutant SUR1 labeling (Fig. 6).
X
ABCC8 p.Trp232Ala 17110465:127:127
status: NEW129 When SUR1 Y230A, and W232A were coexpressed with ⌵⌬33KIR6.2, a KIR6.2 construct that does not photolabel, none of the SUR1 mutants labeled (Fig. 6), indicating that the KIR6.2 N terminus play a role in the sulfonylurea binding pocket.
X
ABCC8 p.Trp232Ala 17110465:129:21
status: NEW184 When SUR1 and the SUR1 alanine point mutations Y230A and W232A were coexpressed with KIR, this resulted in an increase in [125 I]-azido-glibenclamide labeling and KIR cophotolabeling, consistent with KIR forming part of the B site.
X
ABCC8 p.Trp232Ala 17110465:184:57
status: NEW189 Wild-type SUR1, SUR1, Y230A, and W232A were expressed or coexpressed with either KIR6.2 or N⌬33KIR6.2 in COSm6 cells.
X
ABCC8 p.Trp232Ala 17110465:189:33
status: NEW192 However, coexpression of SUR1, Y230A, and W232A with N⌬33KIR6.2 did not increase labeling of SUR1 or the mutants.
X
ABCC8 p.Trp232Ala 17110465:192:42
status: NEW103 The graph shows a decrease in photoaffinity labeling for SUR1 Y230A and W232A (Fig. 3C).
X
ABCC8 p.Trp232Ala 17110465:103:72
status: NEW125 The data are plotted as the ratio of label-to- protein in arbitrary units afe; sd. the SUR1, Y230A, and W232A substitutions.
X
ABCC8 p.Trp232Ala 17110465:125:109
status: NEW128 When SUR1 Y230A, and W232A were coexpressed with टèc;33KIR6.2, a KIR6.2 construct that does not photolabel, none of the SUR1 mutants labeled (Fig. 6), indicating that the KIR6.2 N terminus play a role in the sulfonylurea binding pocket.
X
ABCC8 p.Trp232Ala 17110465:128:21
status: NEW183 When SUR1 and the SUR1 alanine point mutations Y230A and W232A were coexpressed with KIR, this resulted in an increase in [125 I]-azido-glibenclamide labeling and KIR cophotolabeling, consistent with KIR forming part of the B site.
X
ABCC8 p.Trp232Ala 17110465:183:57
status: NEW188 Wild-type SUR1, SUR1, Y230A, and W232A were expressed or coexpressed with either KIR6.2 or Nèc;33KIR6.2 in COSm6 cells.
X
ABCC8 p.Trp232Ala 17110465:188:33
status: NEW191 However, coexpression of SUR1, Y230A, and W232A with Nèc;33KIR6.2 did not increase labeling of SUR1 or the mutants.
X
ABCC8 p.Trp232Ala 17110465:191:42
status: NEW