Lecture 10 Slides rh

A science family tree… Albert Lehninger Eugene Kennedy Christian R. H. Raetz Randolph Y. Hampton

(plural mitochondria) 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 impermeable to most small molecules 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+2 Fe+3 + e- 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

how do we know it’s a chain? 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

Don’t waste clean thinking on dirty enzymes a message from Efraim fig19-7

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

a Cu-S complex! fig19-13

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!