Power Conversion in Mitochondria II Flashcards
What is complex II also known as?
Succinate Dehydrogenase
How many protein make up complex II?
4
What cofactors does complex II contain?
- FAD
- 3FeS centres
- b-type heme
What is reduced as succinate is oxidised in complex II?
FAD
How are the proteins arranged in complex II?
- 2 proteins in matrix
- 2 proteins in membrane
What happens in Complex II?
- FAD reduced and succinate oxidised
- electron moves up FeS centres to heme and used to reduce quinone pool
Are protons pumped in complex II?
No as protons are taken from the matrix side
What is complex III also known as?
bc1 complex
What is the structure of complex III?
- Dimer of 11 different subunits
- Each monomer has 3 core subunits
What are the 3 core subunits of complex III monomers?
- Rieske (FeS) protein
- Cytochrome b
- Cytochrome c1
What mechanism is used to pump H+ by complex III?
Direct mechanism
What happens in complex III?
- Modified Q cycle
- Reduction of cytochrome c, oxidation of ubiquinol to ubiquinone
How many Cyt c1 are reduced by 1 electron in complex III?
2
How many H+ does the Q cycle transport in 1 ‘turn’?
4
What does cytochrome c do?
Picks up electrons from complex III and delivers to complex IV
What is complex IV also known as?
Cytochrome c oxidase
What cofactors does complex III contain?
- FeS in Rieske protein
- Heme from cytochromes
What redox does Complex IV contain?
- CuA
- CuB
- Haem a
- Haem a3
How are the Cu atoms in CA of complex IV arranged?
2Cu atoms are co-ordinated by Cys and His sidechains
What is the structure of complex IV?
Dimer of 13 different subunits
Which subunits of complex IV contain redox centres?
Subunit I and II
How many electrons are moved per O2 in complex IV?
4 electrons
How many H+ are moved per 4 electrons in complex IV?
4
Passing 2 electrons from NADH to 1/2 O2 results in how many H+ being pumped?
10 H+
Passing 2 electrons from succinate to 1/2 O2 results in how many H+ being pumped?
6H+
