Embed Size (px)
Citation preview
Mitochondrion. Synthesis of ATP.
1. ATP universal energy “currency”
2. Structure of mitochondrion
3. Chemiosmotic theory
4. Synthesis of ATP
5. Biogenesis of mitochondrion
Lodish et al.: Molecular Cell Biology (4th ed.)
16.1 Oxidation of Glucose and Fatty Acid to CO2
16.2 Electron Transport and Oxidative Phosphorylation
17.1 Synthesis and Targeting of Mitochondrial
and Chloropast proteins
9.7 Organelle DNAs
Alberts et al.: Essential Cell Biology 4th ed.
Chapter 14. pages 447-469, 479-481.
Chapter 15. pages 487-497.
Key words:
ATP; Glycolysis; ATP synthase; anaerobic metabolism;
chemiosmotic theory; mitochondrial matrix; christae;
mitochondria; chloroplasts; oxidative phosphorylation;
electrochemical proton gradient; inner membrane;
outer membrane; intermembrane space; porin; cardiolipin;
mitochondrial DNA; mitochondrial DNA coding;
mitochondrial ribosome; protein import into mitochondria;
respiratory chain; targeting sequence; heat shock protein70;
heat shock protein60; thermogenin;
proofs for bacterial origin of mitochondrium;
1. ATP universal energy “currency”
ATP4- + H2O = ADP3- + P
i(ΔG = - 30.6 kJ/mol)
- glycolytic pathway (1 glucose 2 ATP)
- Photosynthesis (light energy)
- Oxidative phosporylation (presence of oxigen,
chemical energy)
C6H
12O
6+ 6O
2+ 32 Pi2- + 32ADP3- + 32H+ → 6CO
2+ 32ATP4- + 38H
2O
1. ATP universal energy “currency”
1. ATP universal energy “currency”
Anaerobic metabolism
1. ATP universal energy “currency”
2. Structure of mitochondrion
Structure of mitochondrion
-Outer membrane, 50% protein, 50% lipid, role of porin (5 kDa)
-Inner membrane, 76% protein, 24% lipid, role of cardiolipin
-Intermembrane space
-Matrix, citric acid cyle, oxidation of pyruvate, fatty acids
-Cristae, increase in membrane surface
2. Structure of
mitochondrion
2. Structure of mitochondrion
Molecules upto 5000 Da
can go through the outer
membrane of the
mitochondrium
Porin
2. Structure of mitochondrion
Insulation of innermembrane
Hydrogen ion cannot flow through
Cardiolipin has four fatty acid chains!
2. Structure of mitochondrion
2. Structure of mitochondrion
2. Structure of mitochondrion
Movie
3. Chemiosmotic theory
Chemiosmotic theory
-proton motive force (electrochemical potential)
-Generation of proton gradient
-Use of proton gradient
-Experiment demonstration that chemiosmosis is universal
3. Chemiosmotic theory
Concentration gradient
+
Potential difference
=
Electrochemical potential
μH
+1
= μ0
H+1
+ RT ln cH
+1
+ zFΨ1
μH
+2
= μ0
H+2
+ RT ln cH
+2
+ zFΨ2
ΔG = n Δ μ = RT ln(c1/c
2) + 1FΔΨ
Gibbs free = concentration + Potential
energy gradient difference
Electrochemical Potential
3. Chemiosmotic theory
ΔpH ΔΨ
ΔpH ΔGpH
ΔΨ ΔGΨ
ΔGtotal
Mitochondr. 1.0 pH - 5.8 kJ - 160 mV - 15.4 kJ - 21.2 kJ
Chloroplast 3.5 pH - 20.3 kJ 0 0 - 20.3 kJ
Bacterium 2.0 pH - 11.6 kJ - 70 mV - 6.7 kJ - 18.3 kJ
Concentration gradient Potential difference+Total Gibbs
Free Energy=
Energy content of the proton gradient
3. Chemiosmotic theory
3. Chemiosmotic theory
Thylakoid
3. Chemiosmotic theory
Generation of proton gradient
Peter Mitchell, 1978
3. Chemiosmotic theory
Generation of
Proton gradient
3. Chemiosmotic theory
Use of proton gradient
Thermogenin protein
(MW. 33,000) (UCP)
Brown fat tissue
Cold adapted animals
Other use of proton gradient
Heat production (thermogenin)
Cold adapted animals
Infant
Brown fat tissue
3. Chemiosmotic theory
(thermogenin, UCP)
3. Chemiosmotic theory
Use of proton gradient (16x16 proton per revolution)
Flagellum
3. Chemiosmotic theory
Use of proton gradient - transport
3. Chemiosmotic theory
Chemiosmosis is universal
4. Synthesis of ATP
Synthesis of ATP
-Structure of F0-F
1complex
-ATP synthase as a rotor
-Experiment showing rotation of ATP synthase complex
4. Synthesis of ATP
Structure of F0-F
1complex
4. Synthesis of ATP25nm
8 nm
Paul Boyer
John E. Walker
1997
ATP synthase
as a rotor
4. Synthesis of ATP
4. Synthesis of ATP
Experiment showing rotation of ATP synthase complex
4. Synthesis of ATP
Experiment showing rotation of ATP synthase complex
5. Biogenesis of mitochondrion
Biogenesis of mitochondrion
-Mitochondrial DNA, circular DNA, 5-10 copies
-Alteration in the standard genetic code
-Importing of mitochondrial proteins from the cytosol
uptake-targeting sequences
-Similarities with other organelles (chloroplasts, peroxisomes)
-The origin of mitochondrion
5. Biogenesis of mitochondrion
Euglena gracilis
5. Biogenesis of mitochondrion
Euglena gracilis
Nucleus
Mitochondrion
Mitochondrial DNA
5. Biogenesis of mitochondrion
Human mtDNA 16,569 bp
5. Biogenesis of mitochondrion
Alteration in the universal genetic code
5. Biogenesis of mitochondrion
5. Biogenesis of mitochondrion
Importing cytosolic proteins
5. Biogenesis of mitochondrion
5. Biogenesis of mitochondrion
5. Biogenesis of
mitochondrion
Targeting
cytosolic
proteins
5. Biogenesis of mitochondrion
Similarities with
other cell organelles
5. Biogenesis of mitochondrion
Origin of mitochondria
Mitochondrion. Synthesis of ATP.
1. ATP universal energy “currency”
2. Structure of mitochondrion
3. Chemiosmotic theory
4. Synthesis of ATP
5. Biogenesis of mitochondrion
Proofs that the Mitochondrion
has bacterial origin:
1. Circular DNA. (No chromosomes!)
2. Size of mitochondrion (1 micron!)
3. Two membranes. (Outer membrane => host cell,
inner membrane => bacterium
4. Alteration from the STANDARD CODE!
5. Ribosome (60S, bacterial ribosome)
6. Heat shock protein (Hsp60) resemblance to bacterial Hsp.
The relationship between atmospheric O2
levels
and major stages in evolution of living organisms
Evolution of oxidative
phosphorylation mechanism
(One possible sequence)
