ABCC1 p.Ala1227Lys
| Predicted by SNAP2: | C: N (66%), D: N (53%), E: D (71%), F: D (63%), G: N (82%), H: D (75%), I: D (63%), K: D (75%), L: D (71%), M: D (63%), N: D (63%), P: N (93%), Q: D (59%), R: D (75%), S: N (93%), T: D (53%), V: D (53%), W: D (80%), Y: D (71%), |
| Predicted by PROVEAN: | C: D, D: N, E: N, F: D, G: N, H: D, I: D, K: N, L: D, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: D, |
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[hide] The predicted transmembrane fragment 17 of the hum... Biochim Biophys Acta. 2007 Mar;1768(3):538-52. Epub 2006 Dec 16. Vincent M, Gallay J, Jamin N, Garrigos M, de Foresta B
The predicted transmembrane fragment 17 of the human multidrug resistance protein 1 (MRP1) behaves as an interfacial helix in membrane mimics.
Biochim Biophys Acta. 2007 Mar;1768(3):538-52. Epub 2006 Dec 16., [PMID:17257580]
Abstract [show]
The human multidrug resistance protein MRP1 (or ABCC1) is one of the most important members of the large ABC transporter family, in terms of both its biological (tissue defense) and pharmacological functions. Many studies have investigated the function of MRP1, but structural data remain scarce for this protein. We investigated the structure and dynamics of predicted transmembrane fragment 17 (TM17, from Ala(1227) to Ser(1251)), which contains a single Trp residue (W(1246)) involved in MRP1 substrate specificity and transport function. We synthesized TM17 and a modified peptide in which Ala(1227) was replaced by a charged Lys residue. Both peptides were readily solubilized in dodecylmaltoside (DM) or dodecylphosphocholine (DPC) micelles, as membrane mimics. The interaction of these peptides with DM or DPC micelles was studied by steady-state and time-resolved Trp fluorescence spectroscopy, including experiments in which Trp was quenched by acrylamide or by two brominated analogs of DM. The secondary structure of these peptides was determined by circular dichroism. Overall, the results obtained indicated significant structuring ( approximately 50% alpha-helix) of TM17 in the presence of either DM or DPC micelles as compared to buffer. A main interfacial location of TM17 is proposed, based on significant accessibility of Trp(1246) to brominated alkyl chains of DM and/or acrylamide. The comparison of various fluorescence parameters including lambda(max), lifetime distributions and Trp rotational mobility with those determined for model fluorescent transmembrane helices in the same detergents is also consistent with the interfacial location of TM17. We therefore suggest that TM17 intrinsic properties may be insufficient for its transmembrane insertion as proposed by the MRP1 consensus topological model. This insertion may also be controlled by additional constraints such as interactions with other TM domains and its position in the protein sequence. The particular pattern of behavior of this predicted transmembrane peptide may be the hallmark of a fragment involved in substrate transport.
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No. Sentence Comment
62 Peptides The peptide AGL-VGL-SVS-YSL-QVT-TYL-NWL-VRM-S (Mw=2797) (subsequently referred to as TM17), which encompasses the predicted transmembrane fragment 17 of MRP1, and its N-terminal mutant A1227K (called mTM17) (Mw=2853), were synthesized by Jerini (Berlin, Germany).
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ABCC1 p.Ala1227Lys 17257580:62:194
status: NEW[hide] Interaction with membrane mimics of transmembrane ... Biochim Biophys Acta. 2010 Mar;1798(3):401-14. Epub 2009 Dec 11. de Foresta B, Vincent M, Gallay J, Garrigos M
Interaction with membrane mimics of transmembrane fragments 16 and 17 from the human multidrug resistance ABC transporter 1 (hMRP1/ABCC1) and two of their tryptophan variants.
Biochim Biophys Acta. 2010 Mar;1798(3):401-14. Epub 2009 Dec 11., [PMID:20004175]
Abstract [show]
The human multidrug resistance-associated protein 1 (hMRP1/ABCC1) belongs to the ATP-binding cassette transporter superfamily. Together with P-glycoprotein (ABCB1) and the breast cancer resistance protein (BCRP/ABCG2), hMRP1 confers resistance to a large number of structurally diverse drugs. The current topological model of hMRP1 includes two cytosolic nucleotide-binding domains and 17 putative transmembrane (TM) helices forming three membrane-spanning domains. Mutagenesis and labeling studies have shown TM16 and TM17 to be important for function. We characterized the insertion of the TM16 fragment into dodecylphosphocholine (DPC) or n-dodecyl-beta-d-maltoside (DM) micelles as membrane mimics and extended our previous work on TM17 (Vincent et al., 2007, Biochim. Biophys. Acta 1768, 538). We synthesized TM16 and TM17, with the Trp residues, W1198 in TM16 and W1246 in TM17, acting as an intrinsic fluorescent probe, and TM16 and TM17 Trp variants, to probe different positions in the peptide sequence. We assessed the interaction of peptides with membrane mimics by evaluating the increase in fluorescence intensity resulting from such interactions. In all micelle-bound peptides, the tryptophan residue appeared to be located, on average, in the head group micelle region, as shown by its fluorescence spectrum. Each tryptophan residue was partially accessible to both acrylamide and the brominated acyl chains of two DM analogs, as shown by fluorescence quenching. Tryptophan fluorescence lifetimes were found to depend on the position of the tryptophan residue in the various peptides, probably reflecting differences in local structures. Far UV CD spectra showed that TM16 contained significant beta-strand structures. Together with the high Trp correlation times, the presence of these structures suggests that TM16 self-association may occur at the interface. In conclusion, this experimental study suggests an interfacial location for both TM16 and TM17 in membrane mimics. In terms of overall hMRP1 structure, the experimentally demonstrated amphipathic properties of these TM are consistent with a role in the lining of an at least partly hydrophilic transport pore, as suggested by the currently accepted structural model, the final structure being modified by interaction with other TM helices.
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67 Similarly, a Ala1227Lys mutant of the TM17 fragment (mTM17) containing Trp1246 (or W20) [37] and the Tyr1236Trp and Trp1246Tyr variant of mTM17 (W10-mTM17), with its Trp closer to the extracellular side in the whole protein, were also synthesized (Table 1).
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ABCC1 p.Ala1227Lys 20004175:67:13
status: NEW[hide] Bindings of hMRP1 transmembrane peptides with dode... Biochim Biophys Acta. 2014 Jan;1838(1 Pt B):493-509. doi: 10.1016/j.bbamem.2013.10.012. Epub 2013 Oct 21. Abel S, Lorieau A, de Foresta B, Dupradeau FY, Marchi M
Bindings of hMRP1 transmembrane peptides with dodecylphosphocholine and dodecyl-beta-d-maltoside micelles: a molecular dynamics simulation study.
Biochim Biophys Acta. 2014 Jan;1838(1 Pt B):493-509. doi: 10.1016/j.bbamem.2013.10.012. Epub 2013 Oct 21., [PMID:24157718]
Abstract [show]
In this paper, we describe molecular dynamics simulation results of the interactions between four peptides (mTM10, mTM16, TM17 and KTM17) with micelles of dodecylphosphocholine (DPC) and dodecyl-beta-d-maltoside (DDM). These peptides represent three transmembrane fragments (TM10, 16 and 17) from the MSD1 and MSD2 membrane-spanning domains of an ABC membrane protein (hMRP1), which play roles in the protein functions. The peptide-micelle complex structures, including the tryptophan accessibility and dynamics were compared to circular dichroism and fluorescence studies obtained in water, trifluoroethanol and with micelles. Our work provides additional results not directly accessible by experiments that give further support to the fact that these peptides adopt an interfacial conformation within the micelles. We also show that the peptides are more buried in DDM than in DPC, and consequently, that they have a larger surface exposure to water in DPC than in DDM. As noted previously by simulations and experiments we have also observed formation of cation-pi bonds between the phosphocholine DPC headgroup and Trp peptide residue. Concerning the peptide secondary structures (SS), we find that in TFE their initial helical conformations are maintained during the simulation, whereas in water their initial SS are lost after few nanoseconds of simulation. An intermediate situation is observed with micelles, where the peptides remain partially folded and more structured in DDM than in DPC. Finally, our results show no sign of beta-strand structure formation as invoked by far-UV CD experiments even when three identical peptides are simulated either in water or with micelles.
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No. Sentence Comment
66 As for the TM17 peptide, we carried out MD simulations on two peptides: A first one (TM17) with the native sequence of the peptide and a second one (KTM17), where the first alanine residue was replaced by a lysine (i.e. A1227K).
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ABCC1 p.Ala1227Lys 24157718:66:220
status: NEW313 For the latter one, the A1227K mutation seems to promote the destabilization of the helical structure located above the mutation point at residue positions of L1231-S1236.
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ABCC1 p.Ala1227Lys 24157718:313:24
status: NEW