Electron transport chain,oxidative phosphorylation & mitochondrial transport systems. M.Kohutiar, B.Sopko
Content 1. Structure of mitochondria Mitochondrial transport systems 2. Electron transport 3. Parts of Electron transport chain 4. Proton gradient and synthesis of ATP 5. Uncoupling
Metabolism ANABOLIC CATABOLIC ΔG > 0 ΔG < 0
Gain of electron transport chain C H O 6O 6CO 6H O 6 12 6 2 2 2 0 G 2823kJ / mol
Gain of electron transport chain 1 NADH H O NAD H O 2 2 2 n(adp P ) i n(atp)
Gain of electron transport chain C H O 6O 6CO 6H O 6 12 6 2 2 2 0 G 2823kJ / mol C H O 6O 6CO 6 12 6 2 2 24H 24e 6O 24H 24e 12H O 2 2
Gain of electron transport chain -0,4 NADH COMPLEX I FADH 2 COMPLEX II CoQ COMPLEX III cytochrome c COMPLEX IV 0,8
Gain of electron transport chain -0,4 NADH COMPLEX I FADH 2 COMPLEX II CoQ COMPLEX III cytochrome c COMPLEX IV 0,8
Gain of electron transport chain -0,4 NADH COMPLEX I FADH 2 COMPLEX II CoQ COMPLEX III cytochrome c COMPLEX IV 0,8 ΔE > 0
Gain of electron transport chain 1 NADH H O NAD H O 2 2 2 n(adp P ) i n(atp) -0,4 NADH COMPLEX I FADH 2 COMPLEX II CoQ COMPLEX III cytochrome c COMPLEX IV 0,8
GLYCOLYSIS glucose glucose-6-phosphate glyceraldehyde-3-phosphate NAD + NADH 1,3-bisphosphoglycerate pyruvate NAD + acetyl-coa NADH
GLYCOLYSIS glucose glucose-6-phosphate glyceraldehyde-3-phosphate NAD + acetyl-coa NADH 1,3-bisphosphoglycerate NADH citrate ocalacetate pyruvate NAD + NAD + isocitrate NAD + acetyl-coa NADH malate fumarate CITRATE CYCLE 2-oxoglutarate NADH FADH 2 sukcinate sukcinyl-coa NAD + FAD NADH
Mitochondrial anatomy
ATP ADP translocase
Cofactors structure
Glycerolphosphate shuttle cytosol mitochondria CH 2 OH HC OH CH 2 O P NAD + glycerol-3-phosphate NADH CH 2 OH C O CH 2 O P dihydroxyacetone phosphate
Glycerolphosphate shuttle cytosol mitochondria CH 2 OH HC OH CH 2 O P glycerol-3-phosphate NAD + NADH CH 2 OH C O CH 2 O P dihydroxyacetone phosphate CH 2 OH HC OH CH 2 O P glycerol-3-phosphate FAD FADH 2 CH 2 OH C O CH 2 O P dihydroxyaceton phosphate
Malate-aspartate shuttle cytosol mitochondria HO NAD + NADH O HC CH 2 COOH COOH MDH C COOH CH 2 COOH malate oxalacetate
Malate-aspartate shuttle cytosol mitochondria HO NAD + NADH O HC CH 2 COOH COOH MDH C COOH CH 2 COOH malate oxalacetate malate oxalacetate HO HC COOH CH 2 COOH NAD + MDH NADH O C COOH CH 2 COOH
Malate-aspartate shuttle cytosol mitochondria HO NAD + NADH O HC CH 2 COOH COOH MDH C COOH CH 2 COOH malate oxalacetate malate oxalacetate HO HC COOH CH 2 COOH NAD + MDH NADH O C COOH CH 2 COOH AST Glu Asp ketoglutarate O C COOH (CH 2 ) 2 COOH
Malate-aspartate shuttle HO NAD + NADH O O HC AST CH 2 COOH COOH MDH C COOH CH 2 COOH Glu Asp C COOH (CH 2 ) 2 COOH cytosol malate oxalacetate a-ketoglutarate mitochondria malate oxalacetate a-ketoglutarate HO HC COOH CH 2 COOH NAD + MDH NADH O AST O C COOH CH 2 COOH Glu Asp C COOH (CH 2 ) 2 COOH
Electron transport NAD H 2e NADH E 0 0,32V 1 0 O2 2H 2e H2O E 2 0,82V
Electron transport NAD H 2e NADH E 0 0,32V 1 0 O2 2H 2e H2O E 0,82V 2 E 0 0,82-(-0,32) 1,14 V ΔG 0 zfδf 0 2 F1,14 220 kj/mol
Electron transport ADP P ATP ΔG 0 30,5 kj/mol
Electron transport ADP P ATP ΔG 0 30,5 kj/mol 330,5 218 100 42%
Electron transport ADP P ATP ΔG 0 30,5 kj/mol 330,5 218 100 42% ΔE 0 0 ΔG zf 30500-2F 0,16 V
Electron transport NAD CoQ ox NADH CoQ red ΔE 0 0,36 V ΔG 0-69,5 kj/mol
Electron transport NADH CoQ ox NAD CoQ red ΔE ΔG 0 0 0,36 V -69,5 kj/mol CoQ red cytc ox CoQ ox cytc red ΔE 0 0,19 V ΔG 0-36,7 kj/mol
Electron transport NADH CoQ ox NAD CoQ red ΔE ΔG 0 0 0,36 V -69,5 kj/mol CoQ red cytc ox CoQ ox cytc red ΔE 0 0,19 V ΔG 0-36,7 kj/mol cytc red 1 2 O 2 cytc ox H 2 O ΔE ΔG 0 0 0,58 V -112 kj/mol
Electron transport FADH 2 CoQ ox FAD CoQ red ΔE 0 0,015 V ΔG 0-2,9 kj/mol
-0,4 NADH COMPLEX I FADH 2 COMPLEX II CoQ COMPLEX III cytochrome c COMPLEX IV 0,8
-0,4 FADH 2 COMPLEX II NADH COMPLEX I CoQ COMPLEX III cytochrome c ADP ATP ADP ATP 0,8 COMPLEX IV ADP ATP
-0,4 NADH COMPLEX I ADP rotenone ATP FADH 2 COMPLEX II CoQ COMPLEX III ADP antimycin A ATP cytochrome c 0,8 COMPLEX IV ADP ATP cyanide
[O 2 ] 1 2 3 4 5 6 čas Time
[O 2 ] NAD + 1 2 3 4 5 6 Time
[O 2 ] NAD + 1 rotenon 2 3 4 5 6 čas
[O 2 ] NAD + 1 rotenone 2 3 FADH 2 4 5 6 time
[O 2 ] NAD + 1 rotenone 2 3 FADH 2 antimycin A 4 5 6 Time
[O 2 ] NAD + 1 rotenone 2 3 FADH 2 antimycin A 4 5 cyanide 6 Time
Components of electron transport chain Complex I: NADH ubiquinonreductase NADH CoQ ox NAD CoQ red ΔE ΔG 0 0 0,36 V -69,5 kj/mol
FeS centres
Components of electron transport chain Complex II: succinate ubiquinon reductase FADH 2 CoQ ox FAD CoQ red ΔE 0 0,015 V ΔG 0-2,9 kj/mol
Components of electron transport chain Complex III:ubiquinol-cytC-reductase CoQ red cytc ox CoQ ox cytc red ΔE 0 0,19 V ΔG 0-36,7 kj/mol
Cytochromes
Components of electron transport chain Complex IV: cytochrome c oxidase 2 3 4 cyt c(fe ) 4H O2 4 cyt c(fe ) 2H2O
Oxidative phosphorylation chemiosmotic 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
high H + H + H + H + H + ++++ ++++ ++++ ++++ ++++ ++++ ---- ---- ---- ---- ---- ---- low H + ADP ATP
Proton gradient ΔG RT[pH in ph ex ] zfδ ΔG 0 21,5 kj/mol
Proton gradient ΔG RT[pH in ph ex ] zfδ ΔG 0 21,5 kj/mol Cytosolic side
Mechanism of redox loop Interimemb. space inner membrane e - matrix QH 2 H + QH.
Mechanism of redox loop Interimemb. space inner membrane e - matrix QH 2 QH 2 H + QH.
Mechanism of redox loop Interimemb. space inner membrane matrix e - H + QH 2 QH 2 H + e - cyt b k QH. QH.
Mechanism of redox loop Mezimemb. prostor inner membrane matrix e - H + QH 2 QH 2 H + e - cyt b k QH. QH. H + e - cyt c Q
Mechanism of redox loop Interimemb. space inner membrane matrix e - H + QH 2 QH 2 H + e - cyt b k QH. QH. H + e - Q Q cyt c
Mechanism of redox loop Interimemb. space inner membrane matrix e - H + QH 2 QH 2 H + e - cyt b k QH. QH. e - cyt b T H + e - Q Q cyt c
Mechanism of redox loop Interimemb. space inner membrane matrix e - H + QH 2 QH 2 H + e - QH. cyt b k e - cyt b T e - QH. H + e - Q Q H + cyt c
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 1 3 ADP P NAD cyt c 2 i NADH cyt c 2 1 2 ATP
Regulation of oxidative phosphorylation ATP c cyt NAD 2 1 P ADP c cyt NADH 2 1 2 i 3 ADP ADP.P cyt c cyt c NADH NAD K i 3 2 2 1
Regulation of oxidative phosphorylation ATP c cyt NAD 2 1 P ADP c cyt NADH 2 1 2 i 3 K ATP ADP.P NAD NADH cyt c c cyt i 2 1 3 2 i 3 2 2 1 ADP.P ATP cyt c cyt c NADH NAD K
Uncoupling
Aerobic vs. Anaerobic ATP production Oxidation of 2 e - NADH. 2,5 mol ATP with consumption of 0,5 mol O 2 1 mol of the substrate is oxidised via Complexes I, III, and IV Oxidation of 2 e - FADH 2 1,5 mol ATP 1 mol of the substrate is oxidised via Complexes II, III a IV Total oxidation of 1 mol of glucose yields 30 32 mol ATP,