ABCMdb

ABCC8 p.Asp860Ala

Predicted by SNAP2:	A: D (91%), C: D (85%), E: D (85%), F: D (91%), G: D (91%), H: D (91%), I: D (91%), K: D (95%), L: D (95%), M: D (91%), N: D (91%), P: D (95%), Q: D (91%), R: D (95%), S: D (91%), T: D (91%), V: D (91%), W: D (95%), Y: D (91%),
Predicted by PROVEAN:	A: D, C: 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, W: D, Y: D,

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Publications
[hide] Insight in eukaryotic ABC transporter function by ... FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19. Frelet A, Klein M
Insight in eukaryotic ABC transporter function by mutation analysis.
FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19., 2006-02-13 [PMID:16442101]

Abstract [show]
With regard to structure-function relations of ATP-binding cassette (ABC) transporters several intriguing questions are in the spotlight of active research: Why do functional ABC transporters possess two ATP binding and hydrolysis domains together with two ABC signatures and to what extent are the individual nucleotide-binding domains independent or interacting? Where is the substrate-binding site and how is ATP hydrolysis functionally coupled to the transport process itself? Although much progress has been made in the elucidation of the three-dimensional structures of ABC transporters in the last years by several crystallographic studies including novel models for the nucleotide hydrolysis and translocation catalysis, site-directed mutagenesis as well as the identification of natural mutations is still a major tool to evaluate effects of individual amino acids on the overall function of ABC transporters. Apart from alterations in characteristic sequence such as Walker A, Walker B and the ABC signature other parts of ABC proteins were subject to detailed mutagenesis studies including the substrate-binding site or the regulatory domain of CFTR. In this review, we will give a detailed overview of the mutation analysis reported for selected ABC transporters of the ABCB and ABCC subfamilies, namely HsCFTR/ABCC7, HsSUR/ABCC8,9, HsMRP1/ABCC1, HsMRP2/ABCC2, ScYCF1 and P-glycoprotein (Pgp)/MDR1/ABCB1 and their effects on the function of each protein.

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No. Sentence Comment
316 [143] SUR1 D860A D860A not activated by MgADP in either presence or absence of MgATP. Login to comment

[hide] Identification of a functionally important negativ... Diabetes. 2004 Dec;53 Suppl 3:S123-7. Campbell JD, Proks P, Lippiat JD, Sansom MS, Ashcroft FM
Identification of a functionally important negatively charged residue within the second catalytic site of the SUR1 nucleotide-binding domains.
Diabetes. 2004 Dec;53 Suppl 3:S123-7., [PMID:15561899]

Abstract [show]
The ATP-sensitive K+ channel (KATP channel) couples glucose metabolism to insulin secretion in pancreatic beta-cells. It is comprised of sulfonylurea receptor (SUR)-1 and Kir6.2 proteins. Binding of Mg nucleotides to the nucleotide-binding domains (NBDs) of SUR1 stimulates channel opening and leads to membrane hyperpolarization and inhibition of insulin secretion. To elucidate the structural basis of this regulation, we constructed a molecular model of the NBDs of SUR1, based on the crystal structures of mammalian proteins that belong to the same family of ATP-binding cassette transporter proteins. This model is a dimer in which there are two nucleotide-binding sites, each of which contains residues from NBD1 as well as from NBD2. It makes the novel prediction that residue D860 in NBD1 helps coordinate Mg nucleotides at site 2. We tested this prediction experimentally and found that, unlike wild-type channels, channels containing the SUR1-D860A mutation were not activated by MgADP in either the presence or absence of MgATP. Our model should be useful for designing experiments aimed at elucidating the relationship between the structure and function of the KATP channel.

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Sentences [show]
No. Sentence Comment
5 We tested this prediction experimentally and found that, unlike wild-type channels, channels containing the SUR1-D860A mutation were not activated by MgADP in either the presence or absence of MgATP. Login to comment
77 Effects of the D860A mutation on Mg nucleotide activation. Login to comment
82 Addition of 100 ␮mol/l MgATP produced a greater block of Kir6.2/SUR1-D860A channels than of wild-type channels: 95 Ϯ 1% (n ϭ 3) compared with 85 Ϯ 5% (n ϭ 3) (Fig. 2). Login to comment
84 MgADP was unable to stimulate the activity of channels carrying the D860A mutation in the presence of ATP, in contrast to wild-type channels (Fig. 2). Login to comment
88 A: Macroscopic currents recorded from oocytes coexpressing Kir6.2 and either SUR1, or SUR2B- D860A in response to a series of voltage ramps from -110 to ؉100 mV. 100 ␮mol/l ADP and 100 ␮mol/l ATP were added to the intracellular solution as indicated by the bars. Login to comment
90 B: Mean KATP conductance recorded in response to 100 ␮mol/l ADP, 100 ␮mol/l ATP, or 100 ␮mol/l ADP ؉ 100 ␮mol/l ATP in patches excised from oocytes coexpressing Kir6.2 and either wild-type SUR1 (Ⅺ) or SUR1-D860A (f). Login to comment
104 We ran four simulations: the wild-type model with 1) ATP docked at both NBDs, or 2) ATP docked at NBD1 and ADP docked at NBD2, and 3, 4) the equivalent simulations of the D860A mutant. Login to comment
106 Furthermore, the D860A simulations demonstrate that removal of the negatively charged aspartate disrupts the interaction of R1379 with nucleotide; in contrast to the wild-type simulations, R1379 more strongly interacts with the ATP than with ADP. Login to comment