ABCB1 p.Tyr401Leu
| Predicted by SNAP2: | A: D (85%), C: D (85%), D: D (91%), E: D (91%), F: D (80%), G: D (91%), H: D (85%), 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%), W: D (85%), |
| 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, W: D, |
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[hide] The conserved tyrosine residues 401 and 1044 in AT... Biochemistry. 2006 Jun 20;45(24):7605-16. Kim IW, Peng XH, Sauna ZE, FitzGerald PC, Xia D, Muller M, Nandigama K, Ambudkar SV
The conserved tyrosine residues 401 and 1044 in ATP sites of human P-glycoprotein are critical for ATP binding and hydrolysis: evidence for a conserved subdomain, the A-loop in the ATP-binding cassette.
Biochemistry. 2006 Jun 20;45(24):7605-16., 2006-06-20 [PMID:16768456]
Abstract [show]
Each nucleotide-binding domain (NBD) of mammalian P-glycoproteins (Pgps) and human ATP-binding cassette (ABC) B subfamily members contains a tyrosine residue approximately 25 residues upstream of the Walker A domain. To assess the role of the conserved Y401 and Y1044 residues of human Pgp, we substituted these residues with F, W, C, or A either singly or together. The mutant proteins were expressed in a Vaccinia virus-based transient expression system as well as in baculovirus-infected HighFive insect cells. The Y401F, Y401W, Y1044F, Y1044W, or Y401F/Y1004F mutants transported fluorescent substrates similar to the wild-type protein. On the other hand, Y401L and Y401C exhibited partial (30-50%) function, and transport was completely abolished in Y401A, Y1044A, and Y401A/Y1044A mutant Pgps. Similarly, in Y401A, Y1044A, and Y401A/Y1044A mutants, TNP-ATP binding, vanadate-induced trapping of nucleotide, and ATP hydrolysis were completely abolished. Thus, an aromatic residue upstream of the Walker A motif in ABC transporters is critical for binding of ATP. Additionally, the crystal structures of several NBDs in the nucleotide-bound form, data mining, and alignment of 18,514 ABC domains with the consensus conserved sequence in a database of all nonredundant proteins indicate that an aromatic residue is highly conserved in approximately 85% of ABC proteins. Although the role of this aromatic residue has previously been studied in a few ABC proteins, we provide evidence for a near-universal structural and functional role for this residue and recognize its presence as a conserved subdomain approximately 25 amino acids upstream of the Walker A motif that is critical for ATP binding. We named this subdomain the "A-loop" (aromatic residue interacting with the adenine ring of ATP).
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No. Sentence Comment
86 HighFive insect cells (Invitrogen) were infected with the recombinant baculovirus carrying the wild type and Y401A, Y1044A, Y401A/Y1044A, Y401C, Y401L, and Y401W mutant human MDR1 cDNAs with a His6 tag at the C-terminal end [BV-MDR1(His6)] as described previously (37).
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ABCB1 p.Tyr401Leu 16768456:86:145
status: NEW100 The Pgp‚Mg-8-azido[R-32 P]ADP‚ BeFx or Pgp‚Mg-8-azido[R-32 P]ADP‚Vi preor posthydrolysis transition state conformation was generated as described Table 1: Effect of Substitution of the Conserved Y401 and Y1044 Residues in ATP Sites on Pgp Cell Surface Expression, Transport Function, ATP Binding, Nucleotide Trapping, and Hydrolysisa construct cell surface expressionb (%) transport functionc (%) ATP bindingd (%) ADP-Vi trappinge (%) ATP hydrolysisf (%) wild-type MDR1 100 100 100 100 100 Y401W 100 100 90-95 90-95 85-90 Y401F 95-100 90-100 NTg NTg NTg Y401C 90-95 45-55 50 <20 NTg Y401L 95-100 25-30 30-35 20-25 NTg Y401A 100-110 <2 <15 <2 <2 Y1044W 100 100 NTg NTg NTg Y1044F 95-100 90-100 NTg NTg NTg Y1044C 90-95 <2 NTg NTg NTg Y1044A 100 <2 <5 <2 <2 Y401W/Y1044W 90-95 <2 NTg NTg NTg Y401F/Y1044F 90-95 95-100 NTg NTg NTg Y401C/Y1044C 100 <2 NTg NTg NTg Y401A/Y1044A 90-95 <2 <2 <2 <2 Y401F/Y1044W 100 100 NTg NTg NTg Y401C/Y1044W 100 <2 NTg NTg NTg Y401A/Y1044W 100-110 <2 NTg NTg NTg Y401W/Y1044F 100 100 NTg NTg NTg a The levels of cell surface expression, transport activity, ATP binding, nucleotide trapping, and ATP hydrolysis by the wild-type protein were taken to be 100%, and these activities in mutant Pgps were expressed relative to wild-type levels.
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ABCB1 p.Tyr401Leu 16768456:100:611
status: NEW144 We generated the single mutants Y401A, Y1044A, Y401C, Y1044C, Y401F, Y1044F, Y401W, Y1044W, and Y401L.
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ABCB1 p.Tyr401Leu 16768456:144:96
status: NEW153 Figure 2 illustrates that in a flow cytometry assay HeLa cells expressing wild-type Pgp show a reduced level of accumulation of fluorescent calcein, whereas cells expressing equivalent amounts of Y401L and Y401C mutant Pgps show partial (30-50%) transport function (Table 1).
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ABCB1 p.Tyr401Leu 16768456:153:196
status: NEW169 Binding of 8-Azido[R-32 P]ATP to Wild-Type, Y401A, Y1044A, Y401A/Y1044A, Y401W, Y401C, and Y401L Mutant Pgps.
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ABCB1 p.Tyr401Leu 16768456:169:91
status: NEW175 In Y401L and Y401C mutants, 30-50% of the azidonucleotide was incorporated.
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ABCB1 p.Tyr401Leu 16768456:175:3
status: NEW200 cross-linking with 8-azidoATP at 4 °C, both Y401L and Y401C trap ~20% nucleotide in the presence of vanadate (Table 1).
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ABCB1 p.Tyr401Leu 16768456:200:49
status: NEW264 Similar results were also obtained with Y401L and Y401C mutants (see Table 1).
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ABCB1 p.Tyr401Leu 16768456:264:40
status: NEW297 Consistent with this view is the fact that while mutants Y401L and Y401C are partially (30-50%) functional, mutants Y1044C and Y401C/Y1044C are completely nonfunctional (Table 1).
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ABCB1 p.Tyr401Leu 16768456:297:57
status: NEW[hide] Genomics and the mechanism of P-glycoprotein (ABCB... J Bioenerg Biomembr. 2007 Dec;39(5-6):481-7. Sauna ZE, Kim IW, Ambudkar SV
Genomics and the mechanism of P-glycoprotein (ABCB1).
J Bioenerg Biomembr. 2007 Dec;39(5-6):481-7., [PMID:18058211]
Abstract [show]
The development of effective clinical interventions against multidrug resistance (MDR) in cancer remains a significant challenge. Single nucleotide polymorphisms (SNPs) contribute to wide variations in how individuals respond to medications and there are several SNPs in human P-glycoprotein (P-gp) that may influence the interactions of drug-substrates with the transporter. Interestingly, even some of the synonymous SNPs have functional consequences for P-gp. It is also becoming increasingly evident that an understanding of the transport pathway of P-gp may be necessary to design effective modulators. In this review we discuss: (1) The potential importance of SNPs (both synonymous and non-synonymous) in MDR and (2) How new concepts that have emerged from structural studies with isolated nucleotide binding domains of bacterial ABC transporters have prompted biochemical studies on P-gp, leading to a better understanding of the mechanism of P-gp mediated transport. Our results suggest that the power-stroke is provided only after formation of the pre-hydrolysis transition-like (E.S) state during ATP hydrolysis.
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No. Sentence Comment
78 Y401C and Y401L mutant P-gps showed partial (30-50%) transport function.
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ABCB1 p.Tyr401Leu 18058211:78:10
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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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.Tyr401Leu 25270578:289:414
status: NEW