electron transport chain,oxidative phosphorylation
TRANSCRIPT
Electron transport chain,oxidative phosphorylation & mitochondrial
transport systems.
M.Kohutiar, B.Sopko
Content
1. Structure of mitochondriaMitochondrial transport systems
2. Electron transport3. Parts of Electron transport chain4. Proton gradient and synthesis of ATP5. Uncoupling
Metabolism ANABOLIC CATABOLIC
ΔG < 0 G < 0 ΔG < 0 G > 0
Gain of electron transport chain
O6H6CO6OOHC 2226126
molkJG /2823´0
Gain of electron transport chain
OHNADO2
1HNADH 22
n(ATP))P n(ADP i
Gain of electron transport chain
O6H6CO6OOHC 2226126
molkJG /2823´0
24e24H6CO6OOHC 226126
O12H24e24H6O 22
Gain of electron transport chain
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH2
-0,4
0,8
Gain of electron transport chain
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH2
-0,4
0,8
Gain of electron transport chain
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH2
-0,4
0,8 ΔE°´ > 0
Gain of electron transport chain
OHNADO2
1HNADH 22
n(ATP))P n(ADP i
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH 2
-0,4
0,8
GLYCOLYSIS
glucose
glucose-6-phosphate
glyceraldehyde-3-phosphate
1,3-bisphosphoglycerate
pyruvate
acetyl-CoA
NAD+
NADH
NAD+
NADH
isocitrate
2-oxoglutarate
sukcinyl-CoA
fumarate
malate
sukcinate
ocalacetate
citrate
NAD+
NAD+
NAD+
NADH
NADH
NADH
FADH2
FAD
CITRATE
CYCLE
acetyl-CoA
GLYCOLYSIS
glucose
glucose-6-phosphate
glyceraldehyde-3-phosphate
1,3-bisphosphoglycerate
pyruvate
acetyl-CoA
NAD+
NADH
NAD+
NADH
Mitochondrial anatomy
ATP – ADP translocase
Cofactors structure
Glycerolphosphate shuttle
CH2
CH
CH2
OH
OH
O P
CH2
C
CH2
O
OH
O P
cytosol mitochondria
glycerol-3-phosphate
dihydroxyacetone phosphate
NADH
NAD+
mitochondria
CH2
CH
CH2
OH
OH
O P
CH2
CH
CH2
OH
OH
O P
CH2
C
CH2
O
OH
O P
CH2
C
CH2
O
OH
O P
cytosol mitochondria
glycerol-3-phosphate glycerol-3-phosphate
dihydroxyaceton phosphatedihydroxyacetone phosphate
NADH
NAD+ FAD
FADH2
Glycerolphosphate shuttle
mitochondria
Malate-aspartate shuttle
CH
CH2
COOH
COOH
OH
cytosol mitochondria
malate
C
CH2
COOH
COOH
ONADH
NAD+
MDH
oxalacetate
mitochondria
CH
CH2
COOH
COOH
OH
cytosol mitochondria
malate
CH
CH2
COOH
COOH
OH
C
CH2
COOH
COOH
OC
CH2
COOH
COOH
ONADH
NAD+
NADH
NAD+
MDH MDH
malate
oxalacetate oxalacetate
Malate-aspartate shuttlemitochondria
CH
CH2
COOH
COOH
OH
cytosol mitochondria
malate
CH
CH2
COOH
COOH
OH
C
CH2
COOH
COOH
OC
CH2
COOH
COOH
O
COOH
C
(CH2)2
COOHO
NADH
NAD+
NADH
NAD+
MDH MDH
Glu
AspAST
malate
oxalacetate oxalacetate
ketoglutarate
Malate-aspartate shuttlemitochondria
CH
CH2
COOH
COOH
OH
cytosol mitochondria
malate
CH
CH2
COOH
COOH
OH
C
CH2
COOH
COOH
OC
CH2
COOH
COOH
O
COOH
C
(CH2)2
COOHOCOOH
C
(CH2)2
COOHO
NADH
NAD+
NADH
NAD+
MDH MDH
Glu
Asp
Glu
AspASTAST
malate
oxalacetate oxalacetate
a-ketoglutaratea-ketoglutarate
Malate-aspartate shuttlemitochondria
Electron transport
V32,0E NADH2eHNAD 0´
0,82VE OH2e2HO2
1 0´22
Electron transport
V32,0E NADH2eHNAD 0´
0,82VE OH2e2HO2
1 0´22
V 1,14(-0,32)-0,82E0´
kJ/mol 2201,14F2zFΔFFΔFG 0´0´
Electron transport
kJ/mol 30,5ΔFG ATPPADP 0´
Electron transport
kJ/mol 30,5ΔFG ATPPADP 0´
42%100218
30,53
Electron transport
kJ/mol 30,5ΔFG ATPPADP 0´
42%100218
30,53
V 0,162F-
30500
zF
ΔFGΔFE
0´0´
Electron transport
kJ/mol -69,5ΔFG
V 0,36ΔFE CoQ NADHCoQNAD0´
0´redox
Electron transport
kJ/mol -36,7ΔFG
V 0,19ΔFE cytCCoQcytCCoQ0´
0´redoxoxred
kJ/mol -69,5ΔFG
V 0,36ΔFE CoQ NADCoQNADH0´
0´
redox
Electron transport
kJ/mol -69,5ΔFG
V 0,36ΔFE CoQ NADCoQNADH0´
0´
redox
kJ/mol -36,7ΔFG
V 0,19ΔFE cytCCoQcytCCoQ0´
0´redoxoxred
kJ/mol -112ΔFG
V 0,58ΔFE OHcytCO2
1cytC
0´
0´2ox2red
Electron transport
kJ/mol -2,9ΔFG
V 0,015ΔFE CoQ FADCoQFADH0´
0´redox2
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH 2
-0,4
0,8
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH 2
-0,4
0,8
ADP
ATP
ADP
ADP
ATP
ATP
COMPLEX I
COMPLEX II
COMPLEX III
COMPLEX IV
CoQ
cytochrome c
NADH
FADH 2
-0,4
0,8
ADP
ATP
ADP
ADP
ATP
ATP
rotenone
antimycin A
cyanide
2 3
4 5
6
1[O2]
èasTime
2 3
4 5
6
1[O2]
Time
NAD+
2 3
4 5
6
1[O2]
èas
NAD+
rotenon
2 3
4 5
6
1[O2]
time
NAD+
rotenone
FADH 2
2 3
4 5
6
1[O2]
Time
NAD+
rotenone
FADH 2 antimycin A
2 3
4 5
6
1[O2]
Time
NAD+
rotenone
FADH 2 antimycin A
cyanide
Components of electron transport chainComplex I: NADH ubiquinonreductase
kJ/mol -69,5ΔFG
V 0,36ΔFE CoQ NADCoQNADH0´
0´
redox
FeS centres
Components of electron transport chainComplex II: succinate ubiquinon reductase
kJ/mol -2,9ΔFG
V 0,015ΔFE CoQ FADCoQFADH0´
0´redox2
Components of electron transport chainComplex III:ubiquinol-cytC-reductase
kJ/mol -36,7ΔFG
V 0,19ΔFE cytCCoQcytCCoQ0´
0´redoxoxred
Cytochromes
Components of electron transport chainComplex IV: cytochrome c oxidase
O2H)c(Fecyt 4O4H)c(Fecyt 4 23
22
Oxidative phosphorylationchemiosmotic theory (Mitchell)
• OXPHOS requires intact mitochondrial membrane
• Inner membrane is impermeable for some ions• Electron transport is accompanied by transport
of H+, and development of measurable gradient• Compounds which increase the membrane
permeability do not affect the electron chain but inhibit ATP synthesis
H+
H+
H+
H+
low H+
high H+
ADP ATP
++++ ++++ ++++ ++++ ++++ ++++
---- ---- ---- ---- ---- ----
Proton gradient
kJ/mol 21,5ΔFG zFΔF]pH[pHRTΔFG 0´exin
Proton gradient
kJ/mol 21,5ΔFG zFΔF]pH[pHRTΔFG 0´exin
Cytosolic side
Mechanism of redox loop
QH2
QH.
H+
e-
matrixinner membraneInterimemb.
space
Mechanism of redox loopmatrixinner membrane
Interimemb.space
QH2QH2
QH.
H+
e-
Mechanism of redox loopmatrixinner membrane
Interimemb.space
QH2QH2
QH.
QH.
H+
H+
e-
cyt bk
e-
Mechanism of redox loopmatrixinner membrane
Mezimemb.prostor
QH2QH2
Q
QH.
QH.
H+
H+
H+
cyt c
e-
e-
cyt bk
e-
Mechanism of redox loopmatrixinner membrane
Interimemb.space
QH2QH2
Q Q
QH.
QH.
H+
H+
H+
cyt c
e-
e-
cyt bk
e-
Mechanism of redox loopmatrixinner membrane
Interimemb.space
QH2QH2
Q Q
QH.
QH.
H+
H+
H+
cyt c
e-
e-
cyt bk
e-
e-
cyt bT
Mechanism of redox loopmatrixinner membrane
Interimemb.space
QH2QH2
Q Q
QH.
H+
H+
H+
cyt c
e-
e-
cyt bk
cyt bT
e-
e-
e-
H+
QH.
Structure of Complex V
3D Structure of Complex V
Schematic Structure of Complex V
Dam
Dam
Protonmotiv force and ATP synthesis
ATP synthesis
Regulation of oxidative phosphorylation
ATPccyt NAD2
1PADPccyt NADH
2
1 2i
3
Regulation of oxidative phosphorylation
ATPccyt NAD2
1PADPccyt NADH
2
1 2i
3
ADP
P.ADP
ccyt
ccyt
NADH
NADK i
3
22
1
Regulation of oxidative phosphorylation
ATPccyt NAD2
1PADPccyt NADH
2
1 2i
3
KATP
ADP.P
NAD
NADH
ccyt
ccyt i
2
1
3
2
i
3
22
1
P.ADPATP
ccyt ccyt
NADHNAD
K
Uncoupling
Aerobic vs. Anaerobic ATP production
Oxidation of 2 e- NADH ……. 2,5 mol ATP with consumption of 0,5 mol O2
1 mol of the substrate is oxidised via Complexes I, III, and IV
Oxidation of 2 e- FADH2 …… 1,5 mol ATP1 mol of the substrate is oxidised via Complexes II, III a IV
Total oxidation of 1 mol of glucose yields 30 – 32 mol ATP,