ABCB1 p.Val801Ser
| Predicted by SNAP2: | A: D (53%), C: N (66%), D: D (80%), E: D (75%), F: D (63%), G: D (71%), H: D (75%), I: N (97%), K: D (80%), L: N (87%), M: N (93%), N: D (66%), P: D (71%), Q: D (63%), R: D (75%), S: D (66%), T: D (63%), W: D (80%), Y: D (75%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: N, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, W: D, Y: D, |
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[hide] Locking intracellular helices 2 and 3 together ina... J Biol Chem. 2014 Jan 3;289(1):229-36. doi: 10.1074/jbc.M113.527804. Epub 2013 Nov 25. Loo TW, Clarke DM
Locking intracellular helices 2 and 3 together inactivates human P-glycoprotein.
J Biol Chem. 2014 Jan 3;289(1):229-36. doi: 10.1074/jbc.M113.527804. Epub 2013 Nov 25., [PMID:24275649]
Abstract [show]
The P-glycoprotein (P-gp) drug pump (ABCB1) has two transmembrane domains and two nucleotide-binding domains (NBDs). Coupling of the drug-binding sites in the transmembrane domains to the NBDs occurs through interaction of the intracellular helices (IHs) with residues in the NBDs (IH1/IH4/NBD1 and IH2/IH3/NBD2). We showed previously that cross-linking of cysteines in IH3 and IH1 with a short cross-linker mimicked drug binding as it activated P-gp ATPase activity. Here we show that residue A259C(IH2) could be directly cross-linked to W803C(IH3). Cross-linking was inhibited by the presence of ATP and adenosine 5'-(beta,gamma-imino)triphosphate but not by ADP. Cross-linking of mutant A259C/W803C inhibited its verapamil-stimulated ATPase activity mutant, but activity was restored after addition of dithiothreitol. Because these residues are close to the ball-and-socket joint A266C(IH2)/Phe(1086)(NBD2), we mutated the adjacent Tyr(1087)(NBD2) close to IH3. Mutants Y1087A and Y1087L, but not Y1087F, were misprocessed, and all inhibited ATPase activity. Mutation of hydrophobic residues (F793A, L797A, L814A, and L818A) flanking IH3 also inhibited maturation. The results suggest that these residues, together with Trp(803) and Phe(804), form a large hydrophobic pocket. The results show that there is an important hydrophobic network at the IH2/IH3/NBD2 transmission interface that is critical for folding and activity of P-gp.
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No. Sentence Comment
80 By contrast, the D800A, V801S, S802A, D805A, and D806A mutations in IH3 appeared to have little or no effect on folding as they yielded mature 170-kDa P-gp as their major product.
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ABCB1 p.Val801Ser 24275649:80:24
status: NEW[hide] In silico screening for inhibitors of p-glycoprote... Mol Pharmacol. 2014 Dec;86(6):716-26. doi: 10.1124/mol.114.095414. Epub 2014 Sep 30. Brewer FK, Follit CA, Vogel PD, Wise JG
In silico screening for inhibitors of p-glycoprotein that target the nucleotide binding domains.
Mol Pharmacol. 2014 Dec;86(6):716-26. doi: 10.1124/mol.114.095414. Epub 2014 Sep 30., [PMID:25270578]
Abstract [show]
Multidrug resistances and the failure of chemotherapies are often caused by the expression or overexpression of ATP-binding cassette transporter proteins such as the multidrug resistance protein, P-glycoprotein (P-gp). P-gp is expressed in the plasma membrane of many cell types and protects cells from accumulation of toxins. P-gp uses ATP hydrolysis to catalyze the transport of a broad range of mostly hydrophobic compounds across the plasma membrane and out of the cell. During cancer chemotherapy, the administration of therapeutics often selects for cells which overexpress P-gp, thereby creating populations of cancer cells resistant to a variety of chemically unrelated chemotherapeutics. The present study describes extremely high-throughput, massively parallel in silico ligand docking studies aimed at identifying reversible inhibitors of ATP hydrolysis that target the nucleotide-binding domains of P-gp. We used a structural model of human P-gp that we obtained from molecular dynamics experiments as the protein target for ligand docking. We employed a novel approach of subtractive docking experiments that identified ligands that bound predominantly to the nucleotide-binding domains but not the drug-binding domains of P-gp. Four compounds were found that inhibit ATP hydrolysis by P-gp. Using electron spin resonance spectroscopy, we showed that at least three of these compounds affected nucleotide binding to the transporter. These studies represent a successful proof of principle demonstrating the potential of targeted approaches for identifying specific inhibitors of P-gp.
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No. Sentence Comment
289 TABLE 2 Identification of protein residues in P-gp that were within 5.0 &#c5; of docked inhibitors Compound Compound 19 (ATP-binding site) Compound 29 (Allosteric binding site) Compound 34 (ADP-binding site) Compound 45 (ATP-binding site) Residues within 5.0 &#c5; of docked inhibitors ILE 160 THR 422 ARG 262 ILE 160 GLY 161 VAL 423 THR 483 GLY 161 ASP 164 ALA 424 LEU 516 ASP 164 PHE 399 LEU 552 PRO 517 PHE 399 TYR 401 LEU 554 HIS 518 TYR 401 PRO 402 THR 563 ASP 521 PRO 402 ILE 409 GLU 566 THR 522 ILE 409 ASN 428 ALA 567 LEU 523 LEU 410 SER 429 VAL 569 VAL 524 ASN 428 GLY 430 GLN 570 GLY 525 SER 429 CYS 431 VAL 571 GLU 526 GLY 430 GLY 432 LEU 573 ALA 529 CYS 431 LYS 433 ASP 574 GLN 530 GLY 432 SER 434 ARG 577 LEU 531 LYS 433 THR 435 THR 582 VAL 801 SER 434 GLN 438 ILE 583 SER 802 THR 435 LEU 443 VAL 584 TRP 803 THR 436 TYR 444 ARG 588 PHE 804 GLN 438 GLN 475 SER 590 ASP 805 TYR 444 GLU 556 THR 591 ASN 809 GLN 475 ILE 585 VAL 592 ASN 1043 GLU 556 HIS 587 ARG 593 TYR 1044 ILE 585 PHE 601 ASN 594 PRO 1045 HIS 587 ARG 905 ALA 595 ARG 1047 ARG 905 ILE 1127 ASP 596 VAL 1052 ILE 1127 PHE 1157 VAL 1273 SER 1077 PHE 1157 ILE 1158 GLN 1274 THR 1078 ILE 1158 LEU 1161 GLY 1276 GLN 1081 LEU 1161 PRO 1162 THR 1277 TYR 1087 PRO 1162 ASN 1163 LYS 1278 GLN 1118 ASN 1163 THR 1167 ARG 1279 LYS 1164 VAL 1169 GLN 1280 THR 1167 THR 1174 THR 1174 GLN 1175 GLN 1175 LEU 1176 LEU 1176 SER 1177 SER 1177 GLY 1178 GLY 1178 GLY 1179 GLY 1179 GLN 1180 GLN 1180 Other groups have shown that flavonoids are strong modulators of P-gp activity and that they interact with the NBDs of the enzyme (Di Pietro et al., 2002).
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ABCB1 p.Val801Ser 25270578:289:750
status: NEW