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Lecture 10 Slides

A science family tree…

Albert Lehninger

Christian R. H. Raetz

Eugene Kennedy

Randolph Y. Hampton

fig 19-1

The mitochondrion (plural mitochondria)

fig 19-1

mitochondria (plural…mitochondrion is singular)

outer membrane

inner membrane

matrix

• porins permeable to MW<5000

• impermeable to most small molecules• respiratory chain complexes• ATP-ADP translocases, other transporters• ATP synthase

• pyruvate dehydrogenase complex• Krebs cycle enzymes• many other things (later and before)

• impermeable to most small molecules

NADH: a universal electron carrier

cofactor electron acceptorsnicotinamide nucleotide-linked dehydrogenases

flavoproteins

• NAD+ or NADP+ are acceptors• loosely bound, freely dissociable• true carriers

• 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

cytochromes• heme cofactors• most are integral membrane proteins (not c)

• benzoquinone for 1 or 2 electron• freely diffusable in inner membrane• membrane-bound carrier

iron-sulfer proteins• multiple types of clusters

fig 19-6

Drugs for studying e- transport order

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

fig19-2

Ubiquinone(coenzyme Q)

inner membrane carrier molecules (in the four complexes)

ubiquinone, or coenzyme Q

cytochromes• heme cofactors• most are integral membrane proteins (not c)

• benzoquinone for 1 or 2 electron• freely diffusable in inner membrane• membrane-bound carrier

fig19-3

heme cofactors

Fe+2

Fe+3 + e-

fig 19-4

Spectral properties of cytochromes

inner membrane carrier molecules (in the four complexes)

ubiquinone, or coenzyme Q

cytochromes• heme cofactors• most are integral membrane proteins (not c)

• benzoquinone for 1 or 2 electron• freely diffusable in inner membrane• membrane-bound carrier

iron-sulfer proteins• multiple types of clusters

fig19-5

Iron-sulfur clusters in proteins

how do we know it’s a chain?

order suggested by E values

inhibitor studies on A and D composition

direct biochemical studies (!!)

Respiratory chainElectron transport chain

Reduction potentials in respiration

order suggested by E values…

fig 19-6

inhibitor studies on A and D composition…

fig 19-7

Hard-corebiochemistryfor study ofrespiratorychain

fig19-7

a messagefrom Efraim Don’t waste

clean thinkingon dirty enzymes

fig19-7

direct biochemical studies (!!)…

fig19-7

direct biochemical studies (!!)…

fig19-9

I NADH dehydrogenase“Hp”

fig19-8

II succinate dehydrogenase

III ubiquinone:cytochrome c oxidoreductase fig19-11

fig19-11

III ubiquinone:cytochrome c oxidoreductase

fig19-13

IV cytochrome oxidase

fig19-13a Cu-S complex!

fig19-14

fig19-16 simplified

electron transport chain

fig19-16

electron transport chain

fig19-17

fig19-16

electron transport chain

fig19-17

proton-motive force

23.6 kJ/mole H+

the coupling question…

chemiosmotic hypothesis!

the coupling question…

chemiosmotic hypothesis!