ABCMdb

ABCC8 p.His11Phe

Predicted by SNAP2:	A: N (66%), C: N (57%), D: N (61%), E: N (72%), F: N (72%), G: N (78%), I: N (57%), K: N (72%), L: N (66%), M: N (61%), N: N (93%), P: N (57%), Q: N (78%), R: N (61%), S: N (87%), T: N (72%), V: N (61%), W: N (53%), Y: N (66%),
Predicted by PROVEAN:	A: N, C: N, D: N, E: N, F: N, G: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: N, Y: N,

[switch to compact view]
Comments [show]

None has been submitted yet.

Publications
[hide] Studies of the melatonin binding site location ont... Arch Biochem Biophys. 2008 Sep 1;477(1):12-9. Epub 2008 May 11. Boutin JA, Saunier C, Guenin SP, Berger S, Moulharat N, Gohier A, Delagrange P, Coge F, Ferry G
Studies of the melatonin binding site location onto quinone reductase 2 by directed mutagenesis.
Arch Biochem Biophys. 2008 Sep 1;477(1):12-9. Epub 2008 May 11., [PMID:18502195]

Abstract [show]
Melatonin is a neurohormone implicated in both biorhythm synchronization and neuroprotection from oxidative stress. Its functions are mediated by two G-protein-coupled-receptors (MT1 and MT2) and MT3, which corresponds to quinone oxidoreductase 2 (QR2). To determine the binding site of QR2 for melatonin, point mutations of residues crucial for the enzymatic activity of hQR2 were performed. The substitution of the hydrophobic residues Phe126, Ile128 and Phe178 by tyrosines at the active site significantly increased enzymatic activity and decreased the affinity of a structural analog of melatonin, the 2[(125)I]iodo-MCANAT. The mutation of residues implicated in zinc chelating (His(173); His(177)) had no effect on radioligand binding. Destabilisation of the cofactor FAD by mutation N18E showed that 2[(125)I]iodo-MCANAT binding was closely linked to the conformational integrity of human QR2. Surprisingly, the mutations C222F and N161A, which are distant from the determined binding site of the ligand, increased the affinity of 2[(125)I]iodo-MCANAT for hQR2. What seems to better explain the binding variations among the mutants are the activity recorded with BNAH and coenzyme Q1. Various hypotheses are discussed based on the various parameters used in the study: nature of the substrates and co-substrates and nature of the amino acid changes. This study, which constitutes the first structural analysis of hQR2, should enable to better understand the biological role of melatonin on this enzyme and particularly, the discrepancies between the pharmacologies of the melatonin binding site (MT3) and the QR2 catalytic activity.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
109 Under these conditions, we were able to know as precisely as possible BNAH/Menadione 0 50 100 150 200 250 300 350 H11F N18E F126Y I128Y F131M F178Y H173S H177R C222F N161A QR2T WT Quinone reductase 2 mutants Specificactivity(%ofmildtype) FAD docking Catalytic site Zinc e- coordination transfer *** ** ** *** *** ** ** ** r *** ** ** *** *** ** ** ** Fig. 3. Login to comment
116 QR2 24 kDa LDH 36.5 kDa 40 30 20 KDa N18E C222F F126Y I128Y F131M H173F N161A H173F H177R F178Y CHO QR2T QR2S QR2 24 kDa LDH 36.5 kDa H11F N18E C222F F126Y I128Y F131M H173F N161A H173F H177R F178Y CHO QR2T QR2S hQR2T hQR2S 40 30 20 KDa 193 128 96 64 48 32 24 16 hQR2 (ng) Marqueur Fig. 2. Login to comment
142 To the contrary, two NRH/Coenzyme Q0 0 50 100 150 200 250 300 H11F N18E F126Y I128Y F131M F178YH 173S H177R C222F N161A QR2T WT Specificactivity(%ofwildtype) 0 50 100 150 200 250 300 350 H11F N18E F126Y I128Y F131M F178Y H173S H177R C222F N161A QR2 WT Specificactivity(%ofwildtype) ** * * * * * ** ** * 1 NRH/CoenzyaymQ1 0 50 100 150 200 250 300 350 Quinone reductase2 mutants FAD docking Catalytic site Zinc e- coordination transfer FAD docking Catalytic site Zinc e- coordination transfer ** * * * * * ** ** * ** * * * * ** * * * * * 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 H11F N18E F126Y I128Y F131M F178Y H173S H177R C222F N161A QR2T WT Quinone reductase2 mutants Specicactivity(%ofwildtype) H11F N18E F126Y I128Y F131M F178Y H173S H177R C222F N161A QR2T WT Quinone reductase 2 mutants Specificacvity(%ofwildtype) FAD docking Catalytic site Zinc e- coordination transfer FAD docking Catalytic site Zinc e- coordination transfer ** * * * * ** * * * * * A B C D Fig. 4. Login to comment
150 3 0 50 100 150 200 250 FAD docking Catalytic site Zinc e- coordination transfer * * ** * ** ** [125I]iodo-MCANAT 0 50 100 150 200 250 H11F N18E F126Y I128Y F131M F178Y H173S H177R C222F N161A QR2T WT Quinone reductase 2 mutants Specicbinding(%ofwildtype) tic * * ** * ** ** Fig. 5. Login to comment
199 When the FAD binding was altered, the enzymatic activities were diminished (N18E) or unchanged (H11F). Login to comment
202 One might hypothesize that FAD orientation is not dramatically altered in the mutant H11F, and only slightly perturbed in N18E, a mutant having half the activity of the wild type. Login to comment
229 To answer clearly to some of these questions, a complete study of redox potential measurements of the Table 4 Summary and comparison of the data obtained on the catalytic activity of or [125I]iodo-MCANAT binding onto quinone reductase 2 Function of QR2 Name of mutant BNAH/Mena BNAH/Q0 BNAH/Q1 NRH/Q0 NRH/Q1 Binding FAD docking H11F 85 132 105 108 87 71 N18E 62 51 53 89 50 46 Catalytic site F126Y 261 271 276 253 268 42 I128Y 161 124 82 51 68 21 F131M 283 115 199 83 133 116 F178Y 291 192 179 180 255 45 Zinc coordination H173S 41 28 46 15 16 75 H177R 100 66 138 30 43 116 C222F 160 97 212 46 70 200 Electron transfer N161A 244 122 211 103 173 194 Note: data are from the Figs. Login to comment
234 As a summary, in the present study, the H11F, N18E, F126Y, I128Y, F131Y, N161A, H177S, H178R, F178Y and C222F mutants were produced. Login to comment