Lecture 10 Slides
rh
A science family tree…
Albert Lehninger
Eugene Kennedy
Christian R. H. Raetz
Randolph Y. Hampton
The mitochondrion
(plural mitochondria)
fig 19-1
fig 19-1
mitochondria (plural…mitochondrion is singular)
outer membrane
•porins permeable to MW<5000
inner membrane
•impermeable to most small molecules
•respiratory chain complexes
•ATP-ADP translocases, other transporters
•ATP synthase
matrix
•pyruvate dehydrogenase complex
•Krebs cycle enzymes
•many other things (later and before)
NADH: a universal electron carrier
cofactor electron acceptors
nicotinamide nucleotide-linked dehydrogenases
•NAD+ or NADP+ are acceptors
•loosely bound, freely dissociable
•true carriers
flavoproteins
•FMN and FAD isoalloxazine acceptors
•tightly bound to enzymes
•single or two electron transfers
inner membrane carrier molecules
(in the four complexes)
ubiquinone, or coenzyme Q
•benzoquinone for 1 or 2 electron
•freely diffusable in inner membrane
•membrane-bound carrier
cytochromes
•heme cofactors
•most are integral membrane proteins (not c)
iron-sulfer proteins
•multiple types of clusters
Drugs for studying e- transport order
fig 19-6
inner membrane carrier molecules
(in the four complexes)
ubiquinone, or coenzyme Q
•benzoquinone for 1 or 2 electron
•freely diffusable in inner membrane
•membrane-bound carrier
Ubiquinone
(coenzyme Q)
fig19-2
inner membrane carrier molecules
(in the four complexes)
ubiquinone, or coenzyme Q
•benzoquinone for 1 or 2 electron
•freely diffusable in inner membrane
•membrane-bound carrier
cytochromes
•heme cofactors
•most are integral membrane proteins (not c)
heme cofactors
Fe+3 + e-
Fe+2
fig19-3
Spectral properties of cytochromes
fig 19-4
inner membrane carrier molecules
(in the four complexes)
ubiquinone, or coenzyme Q
•benzoquinone for 1 or 2 electron
•freely diffusable in inner membrane
•membrane-bound carrier
cytochromes
•heme cofactors
•most are integral membrane proteins (not c)
iron-sulfer proteins
•multiple types of clusters
Iron-sulfur clusters in proteins
fig19-5
Respiratory chain
Electron transport chain
how do we know it’s a chain?
order suggested by E values
inhibitor studies on A and D composition
direct biochemical studies (!!)
Reduction potentials in respiration
order suggested by E values…
inhibitor studies on A and D composition…
fig 19-6
Hard-core
biochemistry
for study of
respiratory
chain
fig 19-7
a message
from Efraim
fig19-7
Don’t waste
clean
thinking
on dirty
enzymes
direct
biochemical
studies (!!)…
fig19-7
direct biochemical studies (!!)…
fig19-7
I NADH dehydrogenase
“Hp
”
fig19-9
II succinate dehydrogenase
fig19-8
III
ubiquinone:
cytochrome c
oxidoreductase
fig19-11
III
ubiquinone:
cytochrome c
oxidoreductase
fig19-11
IV cytochrome oxidase
fig19-13
fig19-13
a Cu-S complex!
fig19-14
electron transport chain
fig19-16 simplified
electron transport chain
fig19-16
fig19-17
electron transport chain
fig19-16
fig19-17
proton-motive force
23.6 kJ/mole H+
the coupling question…
chemiosmotic hypothesis!
the coupling question…
chemiosmotic hypothesis!