ライフサイエンスコーパス: ubiquinol

1 conserving role coupled to the oxidation of ubiquinol.

2 takes up a proton, possibly sharing it with ubiquinol.

3 te to allow reduction of the Fe-S protein by ubiquinol.

4 as 1.23 times that of the membrane permeable ubiquinol.

5 idues altered the affinity of the enzyme for ubiquinol.

6 stoquinol but increases with temperature for ubiquinol.

7 x in the absence of the exogenous substrate, ubiquinol.

8 tics of ISP and cytochrome b(L) reduction by ubiquinol.

9 detected at the Qp site during oxidation of ubiquinol.

10 (QL): an increase in the KM of the substrate ubiquinol-1 (up to 4-fold) and an increase in the appare

11 more, at high concentrations, the substrates ubiquinol-1 and ubiquinol-2 inhibit turnover in an uncom

12 ctroscopy and by determining the activity of ubiquinol-1 oxidase.

13 In each case, the Km for ubiquinol-1 was determined as a measure of possible pert

14 mutant that had a noticeably altered Km for ubiquinol-1 was W136A, in which the Km was about sixfold

15 cilla phospholipids, it was reduced by Q1H2 (ubiquinol-1) but not by ascorbate/TMPD (N,N,N',N'-tetram

16 We demonstrate that ubiquinol-10 dissociation is not rate determining and de

17 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectroscopy was used to cha

18 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectroscopy was used to cha

19 bic antioxidants such as alpha-tocopherol or ubiquinol-10.

20 se cytochrome bo3 from Escherichia coli with ubiquinol-2 (UQ2H2) was carried out using substoichiomet

21 ncentrations, the substrates ubiquinol-1 and ubiquinol-2 inhibit turnover in an uncompetitive fashion

22 Using analogs of the respiratory substrates ubiquinol-3 and rhodoquinol-3, we show that the relative

23 of the heme-copper superfamily that utilizes ubiquinol-8 (Q8H2) as a substrate.

24 d expression, or in the riboflavin (ribE) or ubiquinol-8 (ubiH) biosynthetic pathway, which leads to

25 and catalyzes the two-electron oxidation of ubiquinol-8 and four-electron reduction of O(2) to water

26 and catalyzes the two-electron oxidation of ubiquinol-8 and four-electron reduction of O2 to water.

27 nal oxidases that catalyses the oxidation of ubiquinol-8 and the reduction of oxygen to water.

28 ron transfer to cbo3 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectro

29 on transfer to cbo 3 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectro

30 ratory chain, reducing O2 to water and using ubiquinol-8 or menaquinol-8 as its immediate reductant.

31 cbo(3) is mediated by the membrane-localized ubiquinol-8, the physiological electron donor of cbo(3).

32 aprotic medium to probe the oxidation of the ubiquinol analogue, 2,3-dimethoxy-5-methyl-1,4-benzoquin

33 se temperature dependence of the KIE for the ubiquinol analogue.

34 e structural similarities of the heme-copper ubiquinol and cytochrome c oxidase complexes suggest the

35 as essential for electron transfer from both ubiquinol and menaquinol to NapAB.

36 cture and electrochemical properties between ubiquinol and menaquinol.

37 ts (KIEs) at 296 K are 1.87 and 3.45 for the ubiquinol and plastoquinol analogues, respectively, and

38 oxidase that accepts electrons directly from ubiquinol and reduces oxygen to water without involving

39 i, except that it uses menaquinol instead of ubiquinol as a substrate.

40 The apparent K(m) for ubiquinol at the Q(o) site in the presence of proximal Q

41 bc(1) complex is the bifurcated oxidation of ubiquinol at the Qp site.

42 contains residues thought to be involved in ubiquinol binding.

43 ditions and the possible roles of ubiquinone/ubiquinol binding/dissociation in energy conversion.

44 hus, W136 may be at or close to a substrate (ubiquinol)-binding site in cytochrome bo3.

45 structures, these results suggest substrate ubiquinol binds in a fashion similar to that of stigmate

46 quinone binds to only the reduced enzyme and ubiquinol binds to only the oxidized enzyme is shown to

47 -state turnover of the cyt bc1 complex using ubiquinol, but not plastoquinol, as a substrate, leading

48 ee more O(2)(*) generation upon oxidation of ubiquinol by a high potential oxidant, such as cytochrom

49 the yeast cytochrome bc(1) complex oxidizes ubiquinol by an alternating, half-of-the-sites mechanism

50 at generation of O-2 during the oxidation of ubiquinol by the cytochrome bc1 complex results from a l

51 The putative oxidation of ubiquinol by the cytochrome bo3 terminal oxidase of Esch

52 oint potential, confirming that oxidation of ubiquinol by the iron-sulfur protein is the rate-limitin

53 Q(P) pocket through bifurcated oxidation of ubiquinol by transferring its two electrons to a high po

54 s thus inferred that sequential oxidation of ubiquinol (by two sequential n=1 processes) is more rapi

55 When modeled in this way, mucidin and ubiquinol can bind simultaneously to the Q(o) site with

56 dition, mitochondrion-specific antioxidants, ubiquinol conjugated to triphenyl phosphonium, triphenyl

57 nalysis identified ATP synthase gamma chain, ubiquinol-cyt-C reductase, heat shock protein 10 (Hsp10)

58 Ubiquinol cytochrome c oxido-reductase (EC. 1.10.2.2, bc

59 Ubiquinol cytochrome c oxidoreductase (bc1 complex) serv

60 It encodes a 6.6-kD homolog of mitochondrial ubiquinol cytochrome c oxidoreductase (QCR9), subunit 9

61 The interaction of cytochrome c with ubiquinol-cytochrome c oxidoreductase (bc complex) has b

62 Cytochrome c(1) of Rhodobacter sphaeroides ubiquinol-cytochrome c oxidoreductase contains several i

63 mes (aconitase, succinate dehydrogenase, and ubiquinol-cytochrome c oxidoreductase), as well as cytos

64 re stoichiometric inhibitors of complex III (ubiquinol-cytochrome c oxidoreductase), exerting their h

65 in the Rieske iron-sulfur subunit (Rip1) of ubiquinol-cytochrome c reductase (bc1) accumulate a late

66 Ubiquinol-cytochrome c reductase activities of mitochond

67 Ubiquinol-cytochrome c reductase activities of the bc(1)

68 xes (F195Y, F195H, or F195W) having the same ubiquinol-cytochrome c reductase activity as the wild-ty

69 ounced decrease in efficacy of inhibition of ubiquinol-cytochrome c reductase activity by stigmatelli

70 A have, respectively, 78%, 100%, and 100% of ubiquinol-cytochrome c reductase activity found in the w

71 Antimycin stimulated the ubiquinol-cytochrome c reductase activity of the bc(1) c

72 nker region of the Rieske protein lowers the ubiquinol-cytochrome c reductase activity of the mitocho

73 Ilicicolin inhibits ubiquinol-cytochrome c reductase activity of the yeast b

74 ron leakage to oxygen and thus decreases the ubiquinol-cytochrome c reductase activity.

75 e iron-sulfur protein restores 25-30% of the ubiquinol-cytochrome c reductase activity.

76 Out of these, the ubiquinol-cytochrome c reductase core II protein (UQCRC2

77 alize with the mitochondrial matrix protein, ubiquinol-cytochrome c reductase core protein 2 or the i

78 The final step in the assembly of the ubiquinol-cytochrome c reductase or bc(1) complex involv

79 1a, NADH dehydrogenaseB2, and the AAA ATPase Ubiquinol-cytochrome c reductase synthesis1), and intera

80 bilizes the interaction of COX with the bc1 (ubiquinol-cytochrome c reductase) complex.

81 actions between mitochondrial complexes III (ubiquinol-cytochrome c reductase; cyt. bc1) and IV (cyto

82 tallographic structures of the mitochondrial ubiquinol/cytochrome c oxidoreductase (cytochrome bc(1)

83 The mitochondrial cytochrome bc(1) complex (ubiquinol/cytochrome c oxidoreductase) is generally thou

84 he reduction of the bis-heme cytochrome b of ubiquinol: cytochrome c oxidoreductase (complex III, bc1

85 eactions of the bis-heme cytochrome b of the ubiquinol:cytochrome c oxidoreductase complex (complex I

86 is was reduced in respiratory complexes III (ubiquinol:cytochrome c oxidoreductase) and IV (cytochrom

87 fic inhibitor of the cytochrome bc1 complex (ubiquinol:cytochrome c oxidoreductase), blocked almost c

88 Ubiquinol:cytochrome c oxidoreductase, bc1 complex, is t

89 the Rieske iron-sulfur protein (ISP) of the ubiquinol:cytochrome c(2) oxidoreductase (bc(1) complex)

90 ll ubiquinone would be completely reduced to ubiquinol, e.g., by the sulfidequinone oxidoreductase, b

91 However, how ubiquinone/ubiquinol exchange occurs on catalytically relevant time

92 Hence, the protons required for ubiquinol formation must be taken up from the outside of

93 lts from a leakage of the second electron of ubiquinol from its Q cycle electron transfer pathway to

94 ble to oxidize both reduced cytochrome c and ubiquinol in a cyanide sensitive manner.

95 gest that there is only one binding site for ubiquinol in cyt bo3 and that site corresponds to the QH

96 dase catalyzes the two-electron oxidation of ubiquinol in the cytoplasmic membrane of Escherichia col

97 c(1) reduced by several equivalents of decyl-ubiquinol in the presence of antimycin corresponded to o

98 anion (O(2)(*)) generation upon oxidation of ubiquinol in the presence of molecular oxygen.

99 one yet shows the position of the substrate, ubiquinol, in the quinol oxidase (Q(o)) site.

100 by a protonmotive Q cycle mechanism in which ubiquinol is oxidized at one center in the enzyme, refer

101 In this model, ubiquinol is oxidized at one site and ubiquinone is redu

102 t step, ubiquinone is bound and reduced, and ubiquinol is released.

103 hydrochloride-O2* adduct during oxidation of ubiquinol, is 3 times higher in the F195A complex than i

104 case that all ubiquinone has been reduced to ubiquinol its reoxidation by Cox2 will enable the cytoch

105 uggests that the reduced form of ubiquinone (ubiquinol) may also function as a lipid soluble antioxid

106 t with electron transfer mechanisms in which ubiquinol must simultaneously interact with the iron-sul

107 ons in which concentration of one substrate (ubiquinol or ISP(ox)) was saturating and the other was v

108 talyzes the two-electron oxidation of either ubiquinol or menaquinol in the membrane and scavenges O2

109 m = 2-(2-pyridyl)benzimidazolate) oxidizes a ubiquinol or plastoquinol analogue in acetonitrile.

110 ations except R391K result in enzyme lacking ubiquinol oxidase activity.

111 The cytochrome bo3 ubiquinol oxidase catalyzes the two-electron oxidation o

112 The cytochrome bo3 ubiquinol oxidase complex from Escherichia coli contains

113 translocation mechanism for the heme-copper ubiquinol oxidase complexes should be further investigat

114 The cytochrome bo3 ubiquinol oxidase contains at least one and possibly two

115 The purified Escherichia coli cytochrome bo3 ubiquinol oxidase contains four subunits that are each i

116 The ubiquinol oxidase cytochrome bo3 from Escherichia coli i

117 rolled by regB-regA, fnrL, and hvrA and that ubiquinol oxidase expression is controlled by regB-regA,

118 The R481 residue of cytochrome bo(3) ubiquinol oxidase from E. coli is highly conserved in th

119 The cytochrome bo(3) ubiquinol oxidase from Escherichia coli resides in the b

120 The cytochrome bo3 ubiquinol oxidase from Escherichia coli resides in the b

121 5)N isotope labeling of the cytochrome bo(3) ubiquinol oxidase from Escherichia coli with auxotrophs

122 An ubiquinol oxidase from Escherichia coli, cytochrome bo(3

123 very close homologue of the cytochrome bo(3) ubiquinol oxidase from Escherichia coli, except that it

124 lls harbouring CpcA-labelled cytochrome bd 1 ubiquinol oxidase in the cytoplasmic membrane show that

125 Vitreoscilla cytochrome bo ubiquinol oxidase is similar in some properties to the E

126 ults were obtained for cytochrome bo(3), the ubiquinol oxidase of Escherichia coli.

127 cytochrome b to restore an apparently normal ubiquinol oxidase site, but that interaction between the

128 teraction of Rc_sR42 with cydA (cytochrome d ubiquinol oxidase subunit I).

129 native oxidase (AOX) is a non-proton-pumping ubiquinol oxidase that catalyzes the reduction of oxygen

130 idase (AOX) in plants is a non-proton-motive ubiquinol oxidase that is activated by redox mechanisms

131 brane of Escherichia coli, overexpressing an ubiquinol oxidase, cytochrome bo 3 (cbo 3), was "tethere

132 brane of Escherichia coli, overexpressing an ubiquinol oxidase, cytochrome bo3 (cbo3), was "tethered"

133 r aerobic respiration, cytochrome cbb(3) and ubiquinol oxidase.

134 ncodes a microaerobically-expressed bb3-type ubiquinol oxidase.

135 h-affinity Q(H) site in the cytochrome bo(3) ubiquinol oxidase.

136 gues of the heme/Cu site in cytochrome c and ubiquinol oxidases has been studied in aqueous buffers.

137 ly controls synthesis of cytochrome cbb3 and ubiquinol oxidases that function as terminal electron ac

138 nce for conformational communication between ubiquinol oxidation (center P) and ubiquinone reduction

139 chrome b(H) complexes at center N and favors ubiquinol oxidation at center P by increasing the amount

140 and high potential redox components control ubiquinol oxidation at center P, consistent with the pro

141 acrylate stilbene, two inhibitors that block ubiquinol oxidation at center P, inhibit the yeast enzym

142 es, have allowed us to demonstrate that: (i) ubiquinol oxidation at the Qo-site of the bc1 complex ha

143 Although direct ubiquinol oxidation by Cox2 conserves less energy than u

144 hrome c oxidation by a cytochrome c oxidase, ubiquinol oxidation by Cox2 is of advantage when all ubi

145 oxidation by Cox2 conserves less energy than ubiquinol oxidation by the cytochrome bc(1) complex foll

146 of b reduction is dependent upon the rate of ubiquinol oxidation by the iron-sulfur protein.

147 vely reproduces key features observed during ubiquinol oxidation by the mitochondrial cytochrome bc1

148 n alternating half-of-the-sites mechanism of ubiquinol oxidation in the bc(1) complex dimer.

149 Together these results indicate that ubiquinol oxidation is a concerted reaction in which bot

150 evidence for the early involvement of ISP in ubiquinol oxidation is not available.

151 esults indicate that atovaquone binds to the ubiquinol oxidation pocket of the bc1 complex, where it

152 en together, these results indicate that the ubiquinol oxidation site at center P is damaged in the b

153 get organisms by specifically binding to the ubiquinol oxidation site at center P of the cytochrome b

154 ing the kinetics of inhibitor binding to the ubiquinol oxidation site at center P.

155 The maximal capacity of the ubiquinol oxidation site in complex III in generating RO

156 Because these inhibitors bind to the ubiquinol oxidation site in the bc(1) complex, we propos

157 One of these binding sites, the ubiquinol oxidation site, is clearly in dynamic equilibr

158 of superoxide production in Complex III, the ubiquinol oxidation site, is situated immediately next t

159 conditions that allow the first turnover of ubiquinol oxidation to be observable in cytochrome c(1)

160 To understand better the mechanism of ubiquinol oxidation, we have examined the interaction of

161 least an order of magnitude than the rate of ubiquinol oxidation.

162 effectively to menaquinol oxidation than to ubiquinol oxidation.

163 binds analogous to reaction intermediates of ubiquinol oxidation.

164 ns in RTN4IP1, which encodes a mitochondrial ubiquinol oxydo-reductase.

165 ome, salicylhydroxamic acid (SHAM)-sensitive ubiquinol:oxygen oxidoreductase known as trypanosome alt

166 In contrast, QH*- serves to oxidize a ubiquinol pool in the course of electron transfer from t

167 a single, universally accessible ubiquinone/ubiquinol pool that is not partitioned or channeled.

168 in the course of electron transfer from the ubiquinol pool to the oxygen-consuming center of termina

169 action centers whose function is to reduce a ubiquinol pool.

170 re, we focus on the mitochondrial ubiquinone/ubiquinol pool.

171 Much evidence suggests that ubiquinol (QH2) functions as an effective antioxidant in

172 tion, as further increases in [NADH] elevate ubiquinol-related complex III reduction beyond the optim

173 itions modified to account for the fact that ubiquinol reoxidation is limited by enzyme activity.

174 itions modified to account for the fact that ubiquinol reoxidation is limited by enzyme activity.

175 traightforward entries to polyethyleneglycol ubiquinol succinate (PQS, n = 2), a designer surfactant

176 te reductase A couples more effectively with ubiquinol than with menaquinol.

177 e bo(3) has a high affinity binding site for ubiquinol that stabilizes a ubi-semiquinone.

178 ermore, when the oxidized enzyme reacts with ubiquinol (the reduced form of the usual electron accept

179 he Rieske iron-sulfur cluster cannot oxidize ubiquinol through center P, rates of reduction of cytoch

180 tochrome b but has no effect on oxidation of ubiquinol through center P.

181 lex catalyzes the transfer of electrons from ubiquinol to cyt c while generating a proton motive forc

182 s that might be important for the binding of ubiquinol to cytochrome bo3.

183 rsion during the transport of electrons from ubiquinol to cytochrome c (or alternate physiological ac

184 Cytochrome bc1 transfers electrons from ubiquinol to cytochrome c and uses the energy thus relea

185 ric enzyme that links electron transfer from ubiquinol to cytochrome c by a protonmotive Q cycle mech

186 ble for the transfer reducing potential from ubiquinol to cytochrome c coupled to the movement of cha

187 It funnels electrons coming from NADH and ubiquinol to cytochrome c, but it is also capable of pro

188 of mitochondria and transfers electrons from ubiquinol to cytochrome c.

189 s required to mediate electron transfer from ubiquinol to cytochrome c1.

190 component in order to shuttle electrons from ubiquinol to cytochrome c1.

191 s by one half and causes the apparent Km for ubiquinol to decrease from 9.3 to 2.6 microM.

192 rotein (ISP) accepts the first electron from ubiquinol to generate ubisemiquinone anion to reduce b(L

193 the transfer of electrons from the substrate ubiquinol to heme b.

194 Electron transfer from ubiquinol to NapAB was totally dependent upon NapGH, but

195 pF, are essential for electron transfer from ubiquinol to NapAB.

196 a Q cycle, as electrons are transferred from ubiquinol to NapC.

197 diiron protein that transfers electrons from ubiquinol to oxygen, reducing the oxygen to water.

198 echanism of divergent electron transfer from ubiquinol to the iron-sulfur protein and cytochrome b(L)

199 inly involved in transferring electrons from ubiquinol to the oxidase.

200 the bc(1) complex is electron transfer from ubiquinol to the Rieske iron-sulfur protein (ISP) at the

201 characterize the diffusion properties of the ubiquinol/ubiquinone in the tethered membrane system.

202 characterize the diffusion properties of the ubiquinol/ubiquinone in the tethered membrane system.

203 the redox potentials of the NADH/NAD(+) and ubiquinol/ubiquinone pools.

204 least one and possibly two binding sites for ubiquinol/ubiquinone.

205 enter), the enzyme is primed to reduce UQ to ubiquinol via FAD.

206 tochrome b reduction by either menaquinol or ubiquinol was rapid and monophasic.

207 '-tetramethyl-p-phenylenediamine in place of ubiquinol was, however, unimpaired by the mutations, ind

208 y for rapid electron transfer from substrate ubiquinol, which binds at a separate site (QL), to heme

209 linker region is critical for interaction of ubiquinol with the bc1 complex, consistent with electron

210 interaction of several inhibitory analogs of ubiquinol with the yeast cytochrome bc(1) complex.