BCMB – 8110 Control of Electron Transfer in Biology 1- Key Concepts -Transfer Potentials -Electron transfer cofactors 2- Overview of the electron transport chain -Complex I -Complex II -Complex III -Complex IV 3- Advanced Concepts in Protein Structure/Function -Mechanisms of redox control -Mechanisms of proton transfer -Mechanisms of electron transfer
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BCMB – 8110 Control of Electron Transfer in Biology 1- Key Concepts -Transfer Potentials -Electron transfer cofactors 2- Overview of the electron transport.
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BCMB – 8110
Control of Electron Transfer in Biology1- Key Concepts
-Transfer Potentials-Electron transfer cofactors
2- Overview of the electron transport chain
-Complex I-Complex II-Complex III-Complex IV
3- Advanced Concepts in Protein Structure/Function-Mechanisms of redox control-Mechanisms of proton transfer-Mechanisms of electron transfer
Transfer Potential and the Meaning of Life
It’s all about energy!
Free Energy and Reduction Potential
Transfer Potential
Electron Carriers – Coenzyme Q
Electron Carriers – Iron Sulfur Clusters
Universal, Mobile Electron Carriers – Ferredoxins
Electron Carriers – Low Potential Ferredoxins
Electron Carriers – Rieske Type Iron Sulfur Clusters
Electron Carriers – Cytochromes
Electron Carriers – Cytochromes
Electron Carriers – Blue Copper Proteins
Electron Carriers – Flavoprotein
Electron Storage in Flavins
Complex III
Cytochrome bc1 Complex (Cont.)
Cytochrome bc1 Complex (Cont.)
Cytochrome bc1 Complex (Cont.)
Controlling Reduction Potentials, ElectronTransferAnd Proton Transfer
Rule #1, In most cases, especially for complex metallocenters, protonand electron transfer are coupled.
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Rubredoxin
Redox Control – Nitrogenase
Redox Control – Nitrogenase
Redox Control – Nitrogenase
Redox Control – Nitrogenase
Structural Models of the P-Cluster
Peters et al. Biochemistry (1997) 36 1181-1187
Redox Control – Nitrogenase
-360
-340
-320
-300
-280
-260
-240
-220
-200E
m2
(mV
)
9.08.58.07.57.06.56.05.5
pH
Slope = -53 mV / pH
pH-dependence for the P Redox Couple2+/1+
Model for P-Cluster Redox and Proton Transfer Reactions
P2+
P1+(H+)P2+(H+)
P1+ PN
PN (H+)
Em2
Em2H
Em1
Em1H
pKa pKa pKa
< -348 mV
> -224 mV
< 6.0 > 8.5 > 8.5
-310 mV
Structural Models of the P-Cluster
Peters et al. Biochemistry (1997) 36 1181-1187
e-
8 H+ + 8e- + N2
2 NH3 + H2
e-
H+
P N P 1+ P 2+pH 7.0-310 mV -260 mV
P N P 1+ P 2+
-310 mV -310 mV
pH 8.0
Cytochrome Oxidase- Proton Transfer
Coupled Proton/Electron transfer – CytochromeOxidase
Coupled Proton/Electron transfer – CytochromeOxidase
Coupled Proton/Electron transfer – CytochromeOxidase
Coupled Proton/Electron transfer – CytochromeOxidase
COX + Cyc c + broken beef heart mitochondria.
Capitanio et al. Biochemistry 42(16) p.4607-4612
Coupled Proton/Electron transfer – CytochromeOxidase
Coupled Proton/Electron transfer – CytochromeOxidase