ABCB1 p.Gly1075Ser
| Predicted by SNAP2: | A: D (85%), C: D (85%), D: D (95%), E: D (95%), F: D (95%), 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 (91%), W: D (95%), Y: D (95%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: 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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[hide] Rapid purification of human P-glycoprotein mutants... J Biol Chem. 1995 Sep 15;270(37):21449-52. Loo TW, Clarke DM
Rapid purification of human P-glycoprotein mutants expressed transiently in HEK 293 cells by nickel-chelate chromatography and characterization of their drug-stimulated ATPase activities.
J Biol Chem. 1995 Sep 15;270(37):21449-52., 1995-09-15 [PMID:7665554]
Abstract [show]
P-glycoprotein containing 10 tandem histidine residues at the COOH end of the molecule was transiently expressed in HEK 293 cells and purified by nickel-chelate chromatography. The purified protein had an apparent mass of 170 kDa, and its verapamil-stimulated ATPase activity in the presence of phospholipid was 1.2 mumol/min/mg of P-glycoprotein. We then characterized P-glycoprotein mutants that exhibited altered drug-resistant phenotypes and analyzed the contribution of the two nucleotide binding folds to drug-stimulated ATPase activity. Mutation of residues in either nucleotide binding fold abolished drug-stimulated ATPase activity. The pattern of drug-stimulated ATPase activities of mutants, which conferred increased relative resistance to colchicine (G141V, G185V, G830V) or decreased relative resistance to all drugs (F978A), correlated with their drug-resistant phenotypes. By contrast, the ATPase activity of mutant F335A was significantly higher than that of wild-type enzyme when assayed in the presence of verapamil (3.4-fold), colchicine (9.1-fold), or vinblastine (3.7-fold), even though it conferred little resistance to vinblastine in transfected cells. These results suggest that both nucleotide-binding domains must be intact to couple drug binding to ATPase activity and that the drug-stimulated ATPase activity profile of a mutant does not always correlate with its drug-resistant phenotype.
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No. Sentence Comment
95 To determine the contribution of either nucleotide-binding domain to drug-stimulatable ATPase activity, mutations were made to the core amino acids (G432S, K433M, G1075S, and K1076M, respectively) of the homology A consensus sequences.
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ABCB1 p.Gly1075Ser 7665554:95:163
status: NEW123 Mutants K433M, G1075S, and K1076M had no detectable ATPase activities and are omitted for clarity.
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ABCB1 p.Gly1075Ser 7665554:123:15
status: NEW[hide] The catalytic cycle of P-glycoprotein. FEBS Lett. 1995 Dec 27;377(3):285-9. Senior AE, al-Shawi MK, Urbatsch IL
The catalytic cycle of P-glycoprotein.
FEBS Lett. 1995 Dec 27;377(3):285-9., [PMID:8549739]
Abstract [show]
P-glycoprotein is a plasma-membrane glycoprotein which confers multidrug-resistance on cells and displays ATP-driven drug-pumping in vitro. It contains two nucleotide-binding domains, and its structure places it in the 'ABC transporter' family. We review recent evidence that both nucleotide-sites bind and hydrolyse Mg-ATP. The two catalytic sites interact strongly. A minimal scheme for the MgATP hydrolysis reaction is presented. An alternating catalytic sites scheme is proposed, in which drug transport is coupled to relaxation of a high-energy catalytic site conformation generated by the hydrolysis step. Other ABC transporters may show similar catalytic features.
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No. Sentence Comment
103 Loo and Clarke [37] extended this approach, showing that the mutations K433M, K1076M, G432S and G1075S in the Homology A sequences of either NBS1 or NBS2 in human Pgp abolish drug-exclusion capability in cells and eliminate ATPase activity in membranes.
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ABCB1 p.Gly1075Ser 8549739:103:96
status: NEW